The legal definition of adultery is voluntary sexual intercourse between a married person and someone other than that person’s spouse, and the consequences range from a mostly symbolic criminal label in about 31 states to real financial losses in divorce, lawsuits by the betrayed spouse in a handful of jurisdictions, and a possible dishonorable discharge for active-duty military members. The criminal statutes rarely get used. The civil and military consequences are where this actually plays out.
What Counts as Adultery
Every legal definition shares two requirements: at least one participant is legally married, and the sexual contact is with someone other than that person’s spouse. The marriage has to be formally recognized by the jurisdiction. Cohabitation, informal partnerships, and long-term relationships that never produced a marriage license fall outside the definition, however committed the couple considers themselves.
The married person’s status is what triggers the classification. A single participant can still be liable in states whose statutes reach both parties. The act must be voluntary on the married person’s part; a forced encounter is a sex crime, not adultery.
Most statutes draw the prohibited conduct narrowly as sexual intercourse. Emotional affairs, explicit texts, online relationships, and physical contact short of intercourse generally don’t satisfy the legal definition. Divorce courts may still treat those behaviors as marital misconduct, but they don’t carry the specific label or the consequences attached to adultery.
Is Adultery a Crime
Roughly 31 states still have criminal adultery statutes on the books. A few classify it as a felony with potential prison time of several years; most treat it as a misdemeanor punishable by modest fines or short jail terms. In practice, these laws gather dust. Prosecutions were rare even before Lawrence v. Texas in 2003, and legal scholars widely view that decision as casting constitutional doubt over any statute criminalizing consensual sexual conduct between adults. Several states have repealed their adultery laws in recent years.
The gap between what’s technically illegal and what’s actually enforced is enormous. District attorneys have little incentive to bring these cases, juries are reluctant to convict, and constitutional challenges hang over any prosecution. The real consequences land in civil court.
How Adultery Affects a Divorce
Every state offers no-fault divorce, so no spouse has to prove the other did anything wrong to end the marriage. Many states also keep fault-based grounds available, and adultery is one of the most common. Choosing to file on fault grounds can matter because it sometimes changes the financial outcome.
Property Division and Dissipation of Assets
When marital money funds an affair, the innocent spouse can ask the court to account for that spending through what’s called dissipation of marital assets. Dissipation happens when one spouse uses shared property for a purpose that benefits only themselves and falls outside the couple’s normal standard of living. Hotel rooms, gifts for a third party, vacations together, and rent on a separate apartment are classic examples. If a judge finds dissipation occurred, the spending spouse may see that amount deducted from their share of the remaining marital estate. A spouse who spent $15,000 of joint savings on an affair might receive $15,000 less when the assets are divided.
Spousal Support
Adultery’s effect on alimony varies widely. Some states explicitly bar an adulterous spouse from receiving spousal support, or at least let the court weigh the misconduct as a factor in the amount and duration. Others follow a purely economic model where marital fault plays no role. Even in states that do consider adultery, it rarely operates as an automatic disqualification. Judges weigh it alongside the length of the marriage, each spouse’s earning capacity, and their financial needs.
Does Adultery Affect Child Custody
An affair does not automatically cost a parent custody or visitation. Custody turns on the child’s best interests, not punishment for a spouse’s behavior. Adultery becomes relevant only if it created a specific risk or harm to the child: a parent who neglected the child while pursuing the relationship, a new partner who poses a safety concern, exposure to inappropriate situations, or pressuring the child to keep secrets from the other parent.
Absent those factors, a parent who committed adultery is generally still treated as a capable caregiver. Judges may adjust custody or visitation when the fallout from an affair genuinely threatens the child’s stability, but the aim is protecting the child, not penalizing the parent.
How Adultery Gets Proved
Direct evidence is hard to come by. Courts have long allowed proof through circumstantial evidence under what’s known as the “inclination and opportunity” standard. The spouse alleging adultery has to show two things: that the parties had a romantic or sexual attraction to each other (inclination), and that they had the private setting and time to act on it (opportunity).
Inclination can be established through romantic messages, public displays of affection, gift-giving, financial support, or witness testimony about intimate behavior. Opportunity usually involves overnight hotel stays, cohabitation, regular private meetings, or travel together. Neither element alone is enough. A flirtatious text thread without any evidence the parties were ever alone together won’t get there, and proof of a shared hotel room means little without evidence of a romantic relationship.
The evidentiary standard in most jurisdictions is “clear and convincing evidence,” which sits above the ordinary civil standard of “more likely than not.” The evidence has to create a firm belief that the affair occurred. In contested cases, hiring a private investigator is common.
Defenses to a Fault-Based Adultery Claim
Divorce law recognizes several traditional defenses when one spouse raises adultery as grounds for ending the marriage.
- Condonation. The innocent spouse forgave the affair and resumed the marital relationship. Reconciliation counts as forgiveness, but it’s conditional: if the affair resumes or new misconduct occurs, the forgiveness is revoked and the earlier acts can be raised again.
- Recrimination. Both spouses engaged in conduct that would independently qualify as grounds for divorce. Where this defense applies, neither spouse can claim fault against the other.
- Connivance. The accusing spouse participated in or encouraged the affair. A spouse who arranged for the other to be alone with a potential partner cannot later claim adultery as grounds.
- Collusion. Both spouses agreed that one would commit adultery specifically to manufacture grounds for divorce. Courts treat this as a fraud on the system and will deny the divorce on those grounds.
Some jurisdictions also impose a statute of limitations on using adultery as a divorce ground. Wait too long after discovering the affair and the court will not grant a fault-based divorce on that basis.
Can You Sue the Other Person
In about six states, yes. Two related claims exist. Alienation of affection targets anyone whose conduct drew the married spouse’s love and loyalty away from the marriage. Criminal conversation requires proof that the third party had sexual intercourse with the married spouse; despite its name, it is a civil lawsuit seeking money damages, not a criminal charge.
Where these claims are available, damages can include compensation for emotional distress, humiliation, loss of the unfaithful spouse’s financial contributions to the household, and in some cases punitive damages. The statute of limitations is typically three years from the last act that gave rise to the claim. These cases can produce substantial verdicts, which is why they still attract attention despite the narrow geography.
Adultery in the Military
Active-duty service members operate under a separate framework. Under Article 134 of the Uniform Code of Military Justice, extramarital sexual conduct is a chargeable offense when it undermines good order and discipline or brings discredit on the armed forces. The prosecution has to prove three elements: that the accused had sexual intercourse with someone, that at least one of the parties was married to someone else at the time, and that the conduct was prejudicial to military discipline or reputation.
That third element is what sets military adultery law apart from the largely unenforced civilian statutes. Commanders look at factors like whether the conduct involved a fellow service member’s spouse, whether it affected unit cohesion, whether it involved a superior-subordinate relationship, and whether it became widely known within the unit. The maximum punishment is a dishonorable discharge, forfeiture of all pay and allowances, and confinement for one year.1Department of Defense. Manual for Courts-Martial Unlike civilian prosecutors, military commanders do bring these charges with some regularity, especially when the affair involves members of the same unit or a power imbalance in rank.
A dishonorable discharge reaches well beyond the military itself. It can affect veteran benefits, future employment, and the right to own firearms. A service member facing these allegations should treat them with the same seriousness as any felony charge.