Is Adultery a Crime?

Adultery laws were originally enacted to protect the institution of marriage. While most states have repealed these laws (some decades ago and others more recently), adultery remains a crime in close to a dozen states.

What Is Adultery?

State laws define adultery a bit differently. But, generally speaking, the crime of adultery occurs when a married person has consensual sexual intercourse with someone who is not their spouse.

Adultery was originally limited to opposite-sex couples. A few states' laws retain this type of language. Most state laws, though, refer to spouses and persons without mentioning specific genders.

States Where Adultery Is a Crime

Adultery remains a crime in Alabama, Arizona, Florida, Georgia, Illinois, Kansas, Michigan, Mississippi, Oklahoma, South Carolina, and Wisconsin. Below are a few examples.

Georgia. "A married person commits the offense of adultery when he voluntarily has sexual intercourse with a person other than his spouse and, upon conviction thereof, shall be punished as for a misdemeanor." (Ga. Code § 16-6-19 (2024).)

Michigan. "Adultery is the sexual intercourse of 2 persons, either of whom is married to a third person. Any person who shall commit adultery shall be guilty of a felony; and when the crime is committed between a married woman and a man who is unmarried, the man shall be guilty of adultery, and liable to the same punishment." (Mich. Comp. Laws §§ 750.29, 750.30 (2024).)

Wisconsin. "Whoever does either of the following is guilty of a Class I felony: (1) A married person who has sexual intercourse with a person not the married person's spouse; or (2) A person who has sexual intercourse with a person who is married to another." (Wis. Stat. § 944.16 (2024).)

Most states have removed their adultery crimes from their laws. More recent repeals of adultery laws include Massachusetts (2018), Utah (2019), Idaho (2022), Minnesota (2023), and New York (2024). North Carolina's adultery law is still on the books but was found unconstitutional in 2006. (N.C. Gen. Stat. § 14-184 (2024); Hobbs v. Smith, WL 3103008.)

Who Can Be Prosecuted for Adultery?

It depends on the state law. In some states, only the married party commits the crime of adultery. In others, both married and unmarried persons commit a crime. Arizona's law reflects the latter version and overrides any decision of the prosecutor to pick and choose who to prosecute—"When the act is committed between parties only one of whom is married, both shall be punished." (Ariz. Rev. Stat. § 13-1408 (2024).)

How Is Adultery Proven?

In criminal cases, it's up to the prosecutor to file the criminal charges and prove the crime beyond a reasonable doubt. The non-offending or innocent spouse may be a witness or supply evidence, but they don't file the criminal charges nor are they in charge of the case. (Although a couple of states require the innocent spouse to file a complaint before prosecutors can move forward with the case.)

The prosecutor must prove beyond a reasonable doubt (a near-certainty standard) that adultery has occurred, which includes proof that a valid marriage existed for one or both of the parties and the parties engaged in sexual intercourse. If one of the offending parties wasn't married, the prosecutor might also need to prove they knew the other party was.

Some states also require the prosecutor to prove that the parties were living in an open state of adultery, meaning proof that the couple lived together openly as if they were married. In these states, secretive extra-marital affairs would not fall under the definition of adultery.

Evidence that might be used to prove adultery charges include witness statements, text messages, emails, phone records, hotel bills, GPS tracking, photos, and videos.

What Are the Penalties for Adultery?

Most states impose misdemeanor penalties for adultery crimes. Michigan, Oklahoma, and Wisconsin make it a felony to commit adultery.

Despite these laws remaining on the books, adultery prosecutions are rare. Prosecutors use their professional discretion to decide what charges to file or not file. Part of this discretion involves evaluating whether prosecution will further public welfare and represents a good use of public resources. Because adultery involves vindication of private interests rather than public welfare, prosecutors don't generally step in.

(Ala. Code § 13A-13-2; Ariz. Rev. Stat. § 13-1408; Fla. Stat. § 798.01; Ga. Code § 16-6-19; 720 Ill. Comp. Stat. 5/11-35; Kan. Stat. § 21-5511; Mich. Comp. Laws §§ 750.29, 750.30; Miss. Code § 97-29-1; Okla. Stat. tit. 21, §§ 871, 872; S.C. Code §§ 16-15-60, 16-15-70; Wis. Stat. § 944.16 (2024).)