Infidelity clauses in Michigan prenuptial agreements occupy a legal gray zone where enforceability remains uncertain due to the absence of binding state precedent. Under MCL 557.28, Michigan courts enforce prenuptial agreements that meet fairness and disclosure requirements, but no Michigan appellate court has directly ruled on whether adultery penalty provisions violate public policy. Couples considering an infidelity clause in Michigan should understand that while the clause may deter misconduct, courts could refuse enforcement if the penalty appears unconscionable or the clause conflicts with Michigan's no-fault divorce framework.
This guide examines the legal landscape for infidelity clauses in Michigan prenups, including drafting requirements, typical financial penalties ranging from $50,000 to $7 million, enforceability factors courts consider, and practical alternatives for protecting yourself financially if your spouse commits adultery.
| Key Facts | Michigan Requirements |
|---|---|
| Filing Fee | $175 (no children) / $255 (with children) |
| Waiting Period | 60 days (no children) / 180 days (with children) |
| Residency Requirement | 180 days state + 10 days county |
| Grounds | No-fault only |
| Property Division | Equitable distribution |
| Prenup Governing Law | MCL 557.28 + common law |
| Adultery Criminal Status | Felony under MCL 750.30 (not prosecuted) |
What Is an Infidelity Clause in a Michigan Prenup
An infidelity clause in a Michigan prenuptial agreement is a contractual provision that imposes specific financial consequences if one spouse commits adultery during the marriage. These clauses typically require the unfaithful spouse to pay a lump sum ranging from $50,000 to several million dollars, forfeit a larger share of marital assets, waive spousal support rights, or accept reduced property distribution percentages. Unlike standard prenup provisions addressing asset protection and debt allocation, infidelity clauses introduce fault-based penalties into what Michigan otherwise treats as a no-fault divorce system under MCL 552.6.
Michigan law recognizes prenuptial agreements under MCL 557.28, which states that a contract relating to property made between persons in contemplation of marriage shall remain in full force after the marriage takes place. The Legislature adopted this statute in 1981, establishing the baseline legal framework for prenuptial agreements. However, the statute does not specifically address lifestyle clauses, moral conduct provisions, or adultery penalties.
The key distinction between property-focused prenup provisions and infidelity clauses lies in their purpose. Standard prenup terms allocate existing and future assets based on ownership and contribution. Infidelity clauses, by contrast, punish behavior deemed morally objectionable, which some courts view as contrary to the no-fault divorce philosophy that Michigan adopted to reduce acrimony and litigation in dissolution proceedings.
Michigan Prenuptial Agreement Requirements Under MCL 557.28
Michigan prenuptial agreements must satisfy specific legal requirements to be enforceable, regardless of whether they contain infidelity clauses. The agreement must be in writing, signed by both parties, and executed voluntarily without fraud, duress, or undue influence. Courts apply a two-step analysis: the agreement must be fair and equitable when signed, and it must not be unconscionable when enforced at the time of divorce.
Full financial disclosure represents a critical requirement under Michigan common law. Each party must provide a complete and accurate statement of assets, liabilities, income, and financial obligations. Failure to disclose material assets can render the entire agreement unenforceable, including any infidelity provisions. Courts have consistently invalidated prenups where one spouse concealed significant wealth or income sources.
| Prenup Requirement | Michigan Standard |
|---|---|
| Written Agreement | Required under MCL 557.28 |
| Both Signatures | Required |
| Voluntary Execution | No duress, coercion, or undue influence |
| Full Disclosure | Complete asset/liability/income statements |
| Independent Counsel | Strongly recommended but not required |
| Consideration | Marriage itself serves as consideration |
| Timing | Before marriage ceremony |
| Notarization | Recommended but not strictly required |
Michigan courts give substantially greater weight to prenuptial agreements where both parties had separate attorneys review the document. While independent legal counsel is not a statutory requirement, its absence creates vulnerability to claims that one spouse did not fully understand the rights being waived. For infidelity clauses specifically, having independent counsel strengthens the argument that both parties knowingly accepted the adultery penalty provisions.
The cost of drafting a prenuptial agreement in Michigan ranges from $599 for online platforms to $1,500-$5,000 when using a family law attorney. The average attorney flat fee for a straightforward Michigan prenup is approximately $750 per spouse, which falls below the national average of $890. Complex agreements involving infidelity clauses, business valuations, or significant assets typically cost more due to additional negotiation and drafting time.
Enforceability of Infidelity Clauses in Michigan: The Legal Gray Zone
Michigan courts have not issued a definitive ruling on whether infidelity clauses are enforceable, creating significant uncertainty for couples who include such provisions. The enforceability question depends on several factors including whether the penalty appears unconscionable, whether the clause conflicts with Michigan's no-fault divorce framework, and whether the clause meets standard contract law requirements.
Michigan adopted no-fault divorce in 1972, allowing either spouse to obtain a divorce by simply stating there has been a breakdown of the marriage relationship to the extent that the objects of matrimony have been destroyed and there remains no reasonable likelihood that the marriage can be preserved. This no-fault standard eliminates the need to prove adultery, cruelty, or other misconduct as grounds for divorce. However, Michigan courts do consider fault as one factor in property division under the Sparks factors, creating a potential argument that infidelity clauses simply contractualize what courts might already consider.
The Sparks v. Sparks decision (440 Mich. 141, 1992) established nine factors Michigan courts apply when dividing marital property: (1) duration of the marriage, (2) contributions to the marital estate including homemaking, (3) age of the parties, (4) health of the parties, (5) life station and standard of living, (6) necessities and circumstances, (7) earning abilities, (8) past relations and conduct including fault, and (9) general principles of equity. Factor eight explicitly allows consideration of fault, suggesting that adultery already affects property division in Michigan.
How Other States Have Ruled on Infidelity Clauses
Examining how other states have addressed infidelity clause enforceability provides guidance for predicting how Michigan courts might rule. States with similar legal frameworks have reached different conclusions, creating a spectrum of approaches from full enforcement to complete rejection.
Florida upheld an infidelity clause in Weymouth v. Weymouth (2012), where the court enforced a prenup provision precluding alimony unless the husband committed infidelity. The husband's cheating triggered the clause, entitling the wife to spousal support she would not otherwise have received. Florida courts treated the infidelity clause as a standard contractual provision subject to ordinary enforcement principles.
Maryland upheld a $7 million infidelity penalty in a postnuptial agreement signed after the husband's first affair. The Lloyd v. Niceta case (485 Md. 422, 2023) enforced the clause requiring the husband to pay seven million dollars within 90 days if found by a preponderance of evidence to have committed adultery, buggery, or sodomy. The court analyzed the provision under standard contract principles rather than applying heightened scrutiny based on the marital context.
| State | Infidelity Clause Ruling | Key Case/Reasoning |
|---|---|---|
| Florida | Enforced | Weymouth v. Weymouth (2012) |
| Maryland | Enforced ($7M penalty) | Lloyd v. Niceta (2023) |
| New Hampshire | Enforced | MacFarlane v. Rich (1989) |
| Texas | Generally enforced | Contract principles apply |
| California | Not enforced | Diosdado v. Diosdado - no-fault policy |
| Hawaii | Not enforced | Crofford v. Adachi (2022) |
| Iowa | Not enforced | Violates no-fault principles |
| Nevada | Not enforced | No-fault state policy |
California rejected a $50,000 infidelity penalty in Diosdado v. Diosdado, holding that such clauses violate the state's foundational no-fault divorce principles. The court reasoned that allowing parties to contractually import fault considerations would undermine the Legislature's decision to remove marital misconduct from divorce proceedings.
Hawaii's Supreme Court in Crofford v. Adachi (2022) ruled that infidelity clauses are always unenforceable in that state because personal conduct is not relevant to asset division and enforcement would require judges to investigate fault, contrary to no-fault policy.
Drafting an Enforceable Infidelity Clause for Michigan
If you choose to include an infidelity clause in your Michigan prenup despite the uncertain enforceability, specific drafting techniques can maximize the likelihood of enforcement. The clause should use clear, unambiguous language that precisely defines what constitutes adultery for purposes of triggering the penalty. Vague references to infidelity without behavioral definitions invite litigation over whether specific conduct qualifies.
Financial penalties must be reasonable and proportionate to survive judicial scrutiny. A clause forfeiting all marital assets for a single act of infidelity is more likely to be deemed unconscionable than a proportionate penalty tied to demonstrable financial or emotional harm. Courts examining infidelity clauses in other states have distinguished between penalties that adjust property distribution (more likely enforced) versus penalties that strip the offending spouse of all rights (less likely enforced).
Reasonable penalty ranges based on cases from other jurisdictions include $50,000-$100,000 for moderate net worth couples, adjustments of 5-10% in property division percentages, forfiture of spousal support claims by the cheating spouse, or predetermined lump sum payments that represent a fraction rather than the entirety of marital wealth.
The infidelity clause should include an explicit acknowledgment that both parties understand the provision, had opportunity to consult with independent legal counsel, and voluntarily accept the consequences described. This acknowledgment paragraph strengthens the argument against later claims of unconscionability or lack of informed consent.
How Adultery Affects Michigan Divorce Without a Prenup
Understanding how adultery affects divorce in Michigan without a prenup clause helps contextualize what an infidelity clause would add or change. Michigan operates as a pure no-fault divorce state, meaning neither spouse must prove misconduct to obtain a divorce. The only ground for divorce under MCL 552.6 is that there has been a breakdown of the marriage relationship to the extent that the objects of matrimony have been destroyed.
However, fault including adultery can still affect property division outcomes. Michigan courts divide marital property under equitable distribution principles found in MCL 552.19, MCL 552.23, and MCL 552.401. The Sparks factors explicitly include past relations and conduct of the parties as one of nine considerations. Judges have discretion to award a larger share of marital property to the innocent spouse if adultery significantly harmed the marriage or depleted marital assets.
Spousal support determinations under MCL 552.23 similarly allow consideration of fault. A court may reduce or deny alimony to a spouse who committed adultery, particularly if the affair involved dissipation of marital funds on the paramour. Conversely, courts may increase support to an innocent spouse who suffered emotional or financial harm from the other spouse's infidelity.
Interestingly, adultery remains a felony crime in Michigan under MCL 750.30, though prosecutors have not charged anyone under this statute in decades. The law requires the aggrieved spouse to file a complaint and limits prosecution to within one year of the offense. While criminal enforcement has effectively ceased, the statutory existence of adultery as a felony could theoretically support arguments that infidelity clauses do not violate Michigan public policy.
Alternatives to Infidelity Clauses in Michigan Prenups
Given the uncertain enforceability of infidelity clauses in Michigan, couples seeking financial protection against adultery should consider alternative approaches with clearer legal standing. These alternatives can achieve similar protective goals while avoiding the enforceability risks associated with explicit adultery penalties.
Property division provisions that favor the financially weaker spouse regardless of fault provide protection without requiring proof of adultery. Instead of triggering penalties based on conduct, these clauses ensure fair distribution that accounts for disparities in earning capacity, career sacrifice, and homemaking contributions. Such provisions align with Michigan's equitable distribution framework and face fewer enforceability challenges.
Spousal support provisions guaranteeing minimum alimony for a specified duration protect a spouse who might otherwise receive nothing if the marriage ends. While these provisions do not punish infidelity directly, they ensure financial security regardless of circumstances. Michigan courts routinely enforce spousal support provisions in prenuptial agreements when the terms appear fair at execution and not unconscionable at enforcement.
Sunset clauses that automatically void the prenup after a certain number of years (commonly 10-20 years) create incentives for maintaining the marriage without explicitly penalizing misconduct. After the sunset period, standard Michigan divorce law applies, which does consider fault as one factor in property division.
Filing for Divorce in Michigan: Requirements and Process
If your marriage ends despite the prenup's infidelity clause, understanding Michigan's divorce filing requirements helps you navigate the process efficiently. Michigan imposes residency requirements that must be satisfied before filing: at least one spouse must have lived in Michigan for 180 days and in the filing county for 10 days immediately preceding the complaint under MCL 552.9.
Michigan divorce filing fees total $175 for cases without minor children or $255 for cases involving children under age 18 as of May 2026. The base filing fee of $150 under MCL 600.2529 applies to all cases, plus a $25 electronic filing system fee. Cases with children carry an additional $80 custody and parenting time fee. Additional costs include $20 per motion filed, $25-75 for service of process, and $80 for the judgment fee at case conclusion.
Michigan imposes mandatory waiting periods after filing: 60 days for divorces without minor children, and 180 days (6 months) for divorces involving minor children. The waiting period begins when the complaint is filed, not when the other spouse is served. Courts cannot shorten the 60-day minimum under any circumstances, though the 6-month period may be reduced upon showing of unusual hardship.
Frequently Asked Questions About Infidelity Clauses in Michigan Prenups
Are infidelity clauses enforceable in Michigan prenuptial agreements?
Michigan courts have not definitively ruled on infidelity clause enforceability, creating legal uncertainty. No Michigan appellate decision directly addresses whether adultery penalty provisions violate public policy under the state's no-fault divorce framework. Couples including such clauses should understand they may not be enforced if challenged.
How much can an infidelity clause require a cheating spouse to pay?
Infidelity clause penalties in enforced cases from other states range from $50,000 to $7 million depending on the couple's wealth. A Maryland court upheld a $7 million penalty in Lloyd v. Niceta (2023), while smaller amounts of $50,000-$100,000 are more common. Penalties must be proportionate to survive unconscionability challenges.
Does Michigan consider adultery when dividing property in divorce?
Yes, Michigan courts may consider adultery as one factor in equitable property distribution under the Sparks factors established in Sparks v. Sparks (440 Mich. 141, 1992). Factor eight explicitly allows consideration of past relations and conduct including fault. However, adultery alone rarely results in dramatic shifts in property division.
What are the requirements for a valid prenup in Michigan?
A valid Michigan prenup under MCL 557.28 must be in writing, signed by both parties, executed voluntarily without duress or fraud, and include full financial disclosure from both spouses. Courts apply a two-part fairness test: the agreement must be fair when signed and not unconscionable when enforced.
Is adultery still a crime in Michigan?
Yes, adultery remains a felony under MCL 750.30, though no one has been prosecuted in decades. The law requires the aggrieved spouse to file a criminal complaint within one year of the offense. Prosecutors uniformly decline to pursue these cases despite the statute remaining on the books.
Can I include a lifestyle clause beyond just infidelity in my Michigan prenup?
Michigan prenups can include various lifestyle clauses addressing weight gain, in-law visits, religious practices, or recreational activities. However, courts may refuse to enforce provisions they deem unconscionable or contrary to public policy. Some courts have invalidated entire prenups containing excessive lifestyle restrictions.
What happens if my spouse contests the infidelity clause during divorce?
Contesting an infidelity clause typically involves disputing either the clause's validity or whether adultery actually occurred. The spouse seeking enforcement bears the burden of proving the affair by a preponderance of evidence. Litigation over whether conduct qualifies as adultery can become invasive, expensive, and emotionally draining for both parties.
Should both spouses have separate attorneys when drafting an infidelity clause?
Yes, independent legal counsel for both parties significantly strengthens the agreement's enforceability. Michigan courts give substantially greater weight to prenups where both spouses had separate attorneys. Without independent counsel, the disfavored spouse can more easily argue they did not understand the infidelity clause's implications.
How does Michigan's pending Senate Bill 160 affect prenup enforceability?
Michigan Senate Bill 160 would adopt the Uniform Premarital and Marital Agreements Act (UPMAA), creating comprehensive prenup legislation for the first time. The bill passed the Senate in June 2025 and awaits House action as of May 2026. If enacted, it would establish clearer standards for prenup validity and enforceability, though it does not specifically address infidelity clauses.
What evidence is needed to prove adultery triggered an infidelity clause?
Proving adultery typically requires demonstrating opportunity (the spouses were together alone) and inclination (romantic interest existed) through circumstantial evidence. Direct evidence such as photographs, text messages, emails, hotel receipts, or witness testimony strengthens the case. The standard of proof in civil cases is preponderance of the evidence, meaning more likely than not.
Disclaimer: Filing fees and court costs current as of May 2026. Verify current fees with your local circuit court clerk before filing, as some counties assess additional local surcharges.