Adultery remains a crime in roughly 16 states, with Michigan, Oklahoma, and Wisconsin treating it as a felony and the rest classifying it as a misdemeanor. These are the states where adultery is illegal on paper, but prosecutions are vanishingly rare. The practical consequences show up elsewhere: in divorce court, in military discipline, and in federal security clearance reviews.
Felony Adultery States
Three states still classify adultery as a felony.
- Michigan. Adultery is a felony. The statute itself does not spell out a specific penalty, but it carries potential prison time and a substantial fine under the state’s general sentencing framework.1Michigan Legislature. MCL Section 750.30
- Oklahoma. A felony punishable by up to five years in prison, a fine of up to $500, or both. The statute reaches both the married person and the other participant, even if that person is single.2Justia Law. Oklahoma Statutes Title 21 Section 21-872 – Punishment for Adultery
- Wisconsin. A Class I felony carrying up to three and a half years in prison and a fine of up to $10,000. Both the married person and their partner can be charged.3Wisconsin State Legislature. Wisconsin Statutes 944.16 Adultery
Misdemeanor Adultery States
The remaining states treat adultery as a misdemeanor, with penalties ranging from a token $10 fine to up to a year in jail.
- Alabama. Class B misdemeanor. The statute requires the parties to “live in cohabitation,” so a single encounter would not satisfy the elements.4Alabama Legislature. Alabama Code Title 13A Section 13A-13-2 – Adultery
- Arizona. Misdemeanor.
- Florida. Second-degree misdemeanor, up to 60 days in jail and a $500 fine. The offense is “living in an open state of adultery,” not a one-time act.5Florida Senate. Florida Statutes Section 798.01 – Living in Open Adultery6Florida Legislature. Florida Statutes Section 775.083 – Fines
- Georgia. Misdemeanor. The statute reaches voluntary sexual intercourse with someone other than a spouse, without any added cohabitation element.7Justia Law. Georgia Code Title 16 Section 16-6-19 – Adultery
- Illinois. Class A misdemeanor, generally up to 364 days in jail and a $2,500 fine. The conduct must be “open and notorious.”8Illinois General Assembly. 720 ILCS 5/11-35 Adultery
- Kansas. Class C misdemeanor, the state’s lowest criminal classification.9Kansas Office of Revisor of Statutes. Kansas Statutes 21-5511 Adultery
- Maryland. Misdemeanor with a maximum fine of $10.10Maryland General Assembly. Maryland Code General Courts and Proceedings Section 10-501
- Mississippi. Up to a $500 fine and six months in jail. The statute covers “unlawful cohabitation” in adultery, requiring more than a single encounter.
- North Carolina. Class 2 misdemeanor. The parties must “associate, bed and cohabit together.”
- North Dakota. Appears in compilations of criminal adultery states, though the statute primarily defines adultery in the context of divorce grounds.
- Rhode Island. Criminal offense carrying a fine.
- South Carolina. Fine of $100 to $500, imprisonment of six months to one year, or both.11South Carolina Legislature. South Carolina Code Title 16 Section 16-15-60 – Adultery or Fornication
- Virginia. Class 4 misdemeanor.
Puerto Rico also maintains a criminal adultery statute. The trend is toward repeal: New York eliminated its 1907 adultery law in November 2024,12New York State Senate. Senate Bill S8744 – Repeals the Crime of Adultery Minnesota removed adultery from its criminal code through an omnibus bill signed by Governor Tim Walz, and Idaho’s repeal took effect July 1, 2022.
What the Statutes Actually Criminalize
Most of these laws do not criminalize what people assume they do. Alabama, Florida, Illinois, Mississippi, and North Carolina all require some form of ongoing cohabitation, open conduct, or notoriety before the behavior becomes criminal.4Alabama Legislature. Alabama Code Title 13A Section 13A-13-2 – Adultery5Florida Senate. Florida Statutes Section 798.01 – Living in Open Adultery8Illinois General Assembly. 720 ILCS 5/11-35 Adultery A single affair conducted discreetly would not meet the elements.
Georgia, Kansas, Oklahoma, and Wisconsin take a broader approach, reaching voluntary sexual intercourse with someone other than a spouse without any extra element of openness.7Justia Law. Georgia Code Title 16 Section 16-6-19 – Adultery9Kansas Office of Revisor of Statutes. Kansas Statutes 21-5511 Adultery In most states that still criminalize the conduct, both the married person and the unmarried participant can be charged.
Why Prosecutions Almost Never Happen
Criminal adultery charges are extraordinarily rare. District attorneys have finite resources and little appetite for prosecuting behavior that most of the public treats as a private matter. A prosecutor who did bring charges would also face constitutional headwinds.
In Lawrence v. Texas (2003), the Supreme Court struck down a Texas sodomy statute and held that the government cannot criminalize private, consensual sexual conduct between adults on the basis of moral disapproval alone. The majority opinion did not directly address adultery, but Justice Scalia warned in dissent that the decision’s logic called state adultery laws into question.13Justia U.S. Supreme Court. Lawrence v. Texas, 539 U.S. 558 (2003) No appellate court has definitively ruled that Lawrence invalidates adultery statutes, but the uncertainty discourages prosecutors from testing it.
These laws stay on the books largely because repeal requires legislative action, and few lawmakers want a vote on record to “legalize adultery” even when the statute does nothing in practice.
Where Adultery Still Has Real Legal Consequences
The Military
Extramarital sexual conduct is prosecutable under Article 134 of the Uniform Code of Military Justice, the general article covering conduct that harms good order and discipline or discredits the armed forces.14Office of the Law Revision Counsel. 10 USC 934 Art. 134 General Article Maximum punishment is a dishonorable discharge, forfeiture of all pay and allowances, and up to one year of confinement. Charges typically follow when the affair involves someone in the same chain of command, the spouse of another service member, or circumstances that visibly undermined a unit.
Security Clearances
Adultery can jeopardize a federal security clearance even where no criminal charge is possible. The adjudicative guidelines flag two concerns: Guideline D (sexual behavior that is criminal, reflects poor judgment, or creates vulnerability to coercion) and Guideline E (personal conduct that increases vulnerability to exploitation or blackmail).15eCFR. 32 CFR Part 147 – Adjudicative Guidelines for Determining Eligibility for Access to Classified Information The driving issue is concealment. An affair you are hiding from a spouse gives an adversary leverage; one that is disclosed carries a very different risk profile. People have lost clearances over affairs, particularly where foreign nationals were involved or the applicant lied during the investigation.
Divorce
The real legal impact of adultery plays out in family court. Every state allows no-fault divorce, but many also permit a spouse to allege fault grounds like adultery, which can waive mandatory separation periods and influence the judge’s handling of finances.
On alimony, outcomes vary sharply by state. Some states bar a spouse who committed adultery from receiving alimony. Others let a judge weigh the affair as one factor among many. A few treat marital misconduct as irrelevant. Where you live determines whether an affair has any financial consequence at all.
On property division, courts generally aim for an equitable split, but an affair can shift the calculation when money was involved. A spouse who spent significant marital funds on the relationship, whether on gifts, travel, hotels, or an apartment, can face a “dissipation of marital assets” claim that reduces their share of the remaining property.
On custody, adultery alone rarely matters. Courts decide custody based on the child’s best interests, and a parent’s extramarital relationship is generally irrelevant unless it directly harmed the child. Judges draw a firm line between being a bad spouse and being a bad parent.
Civil Suits Against the Third Party
A small group of states still allow a spouse to sue the person their partner had an affair with. These claims carry the old common-law names “criminal conversation,” which targets the sexual act, and “alienation of affection,” which targets the broader destruction of the marriage. North Carolina is the most active jurisdiction, and Utah still permits them. New Mexico abolished the cause of action in early 2026. A successful plaintiff can recover compensatory damages for emotional harm and loss of the marital relationship, and in some cases punitive damages. North Carolina juries have returned six- and seven-figure verdicts.
Proving Adultery
Whether the setting is divorce, a civil tort claim, or the rare criminal prosecution, proving adultery typically requires clear and convincing evidence. Direct proof is unusual, so courts have long accepted circumstantial evidence through an “inclination and opportunity” test: evidence that the accused had both a romantic attachment and a realistic opportunity to act on it. In practice that means text messages, emails, hotel records, photographs, and witness testimony.
How the evidence is gathered matters. Federal law prohibits intercepting electronic communications without the consent of at least one party. Installing spyware on a spouse’s phone, setting up covert email forwarding, or logging into accounts without permission crosses into illegal interception, and evidence collected that way can be excluded and can expose the collector to criminal liability. Reading messages already saved on a shared household computer sits in a grayer area that varies by jurisdiction. Anyone weighing this should talk to a family law attorney before collecting evidence that could backfire.