Yes, adultery is a crime in Michigan. Under MCL 750.30, it is classified as a felony, making Michigan one of only three states (along with Oklahoma and Wisconsin) where cheating on a spouse is technically a felony-level offense.1Michigan Legislature. MCL – Section 750.30 In practice, criminal prosecutions almost never happen. The law’s real bite shows up in divorce court, where evidence of an affair can affect property division, spousal support, and custody.
What the Statute Says
MCL 750.30 is short and blunt: any person who commits adultery “shall be guilty of a felony.”1Michigan Legislature. MCL – Section 750.30 When the act involves a married woman and an unmarried man, the statute says the man is equally guilty and subject to the same punishment. The law itself does not define adultery in detail, but Michigan courts have long interpreted it as voluntary sexual intercourse between a married person and someone other than their spouse.
Roughly 16 states still criminalize adultery in some form. Most treat it as a minor offense. Michigan is an outlier for keeping it at the felony level.
Who Can Actually Bring a Charge
This is the detail that explains why the felony statute rarely produces a case. Under MCL 750.31, a prosecution for adultery can only begin on the complaint of the offended husband or wife.2Michigan Legislature. Michigan Compiled Laws 750.31 – Adultery; Complaint and Limitation of Prosecution A neighbor, a coworker, or a prosecutor acting on their own cannot start the case. Only the aggrieved spouse can.
The same statute imposes a one-year deadline. No prosecution can begin more than one year after the offense.2Michigan Legislature. Michigan Compiled Laws 750.31 – Adultery; Complaint and Limitation of Prosecution Miss that window and the criminal option is gone, no matter how strong the evidence.
What the Penalties Would Be
Because MCL 750.30 does not set its own sentencing range, adultery falls under Michigan’s general felony penalty provisions. The commonly cited maximum is up to four years in prison, a fine of up to $5,000, or both. Actual prosecutions are extraordinarily rare. Most prosecutors treat adultery as a private matter, and modern juries have little appetite for convicting someone over an affair.
A felony conviction still carries consequences beyond the sentence itself. A person convicted of a felony in Michigan cannot possess a firearm for at least three years after completing their full sentence, including probation or parole.3Michigan Legislature. MCL – Section 750.224f A felony record can also create barriers to employment, professional licensing, and housing.
Where Adultery Actually Matters: Divorce
Michigan is a no-fault divorce state. Under MCL 552.6, a spouse only has to allege that the marriage has broken down to the point where the relationship cannot be preserved.4Michigan Legislature. Michigan Compiled Laws 552.6 – Complaint for Divorce; Filing; Grounds; Answer; Judgment You do not have to prove your spouse cheated to get divorced, and your spouse does not have to agree.
No-fault filing does not mean fault is irrelevant once a judge starts making decisions. Michigan courts can consider a spouse’s conduct during the marriage when dividing property and deciding on spousal support.5Michigan Legal Help. Introduction to Divorce without Children A judge weighs each spouse’s age, health, earning capacity, contributions to the marital estate, and conduct during the marriage. If an affair led to significant spending on a new partner, hidden accounts, or other waste of marital assets, the other spouse has a stronger argument for a larger share of what remains.
Spousal Support
Judges have discretion to weigh fault when awarding spousal support. If adultery is established, the court may factor it in when deciding whether to award support and how much. It is one element among many, not an automatic penalty.
Custody
Michigan custody decisions turn on 12 “best interests of the child” factors. One is the moral fitness of each parent. A judge evaluating moral fitness may consider whether a parent had an affair the child knew about, how that behavior affected the child, and whether it impaired the parent’s ability to provide a stable environment.6Michigan Legal Help. The Best Interests of the Child Factors
An affair alone does not automatically cost a parent custody. It tends to matter most when it caused real disruption in the child’s life, such as introducing a new partner into the household in a harmful way, or when it consumed so much of the parent’s attention that basic caregiving suffered.
Possible Defenses to a Criminal Charge
If a charge does come, several defenses are available. The most direct one targets knowledge: someone who genuinely did not know their partner was married can argue the relationship was not knowingly adulterous. That argument is stronger when the married partner actively concealed their status.
A second defense challenges the marriage itself. If the underlying marriage is legally void, for example in a bigamy situation or where basic legal requirements were never met, there is no valid marriage and therefore no adultery.
The complaint and timing rules under MCL 750.31 give two more practical defenses. If anyone other than the offended spouse initiated the complaint, the charge fails. If more than a year has passed since the alleged act, the prosecution is time-barred.2Michigan Legislature. Michigan Compiled Laws 750.31 – Adultery; Complaint and Limitation of Prosecution
Efforts to Repeal the Law
Michigan’s adultery statute has survived because repealing it has never been a priority, not because lawmakers actively defend it. In December 2024, the Michigan Senate introduced Senate Bills 1083, 1084, and 1085, which would decriminalize adultery along with other rarely enforced morality statutes. The bills passed unanimously out of committee. Lawmakers have described these statutes as “zombie laws” that stay on the books despite decades of near-total non-enforcement.
Even if the felony classification is eventually removed, evidence of adultery would still be relevant in a divorce, because family courts consider marital conduct independently of the criminal code.