Rumors swirled (archived) across social media in May 2025 that cheating after signing marriage papers would be illegal in 2026.
One popular X post read: "Apparently in 2026 cheating is going to be illegal after getting married."
None of the claims above specified a country where the alleged anti-cheating law would apply. However, we found no evidence that a federal law criminalizing cheating — interpreted here as adultery — would come into effect in 2026 in the U.S.
Adultery is already a felony or misdemeanor in 16 U.S. states and Puerto Rico. In six states, people can sue a third party to the marriage for "alienation of affection" if that party caused the marriage to end. Searches on online search engines found no credible reports about pending state or federal laws criminalizing adultery, which would undoubtedly be well-reported if true (archived) (archived) (archived) (archived).
We reached out to the American Academy of Matrimonial Lawyers and the International Academy of Family Lawyers, two U.S.-based organizations focusing on family law, to ask if they knew of any such legislation underway in the U.S. and await their reply.
The claim circulated since at least April 2025 (archived) and gained (archived) popularity (archived) among South African creators on TikTok.
An assistant to Amy Bernard, a family lawyer in South Africa who runs a TikTok page about family law, said via email that the claim was "not true." Family and divorce lawyer Bertus Preller, of Maurice Phillips Wisenberg, a Cape Town-based law firm, said: "The claim circulating among South African content creators is demonstrably false. There is no pending legislation to criminalize adultery in 2026, and such legislation would face significant constitutional challenges given recent court precedents."
We found no credible reporting in online searches to indicate that a law criminalizing adultery would come into effect in South Africa in 2026 (archived) (archived) (archived) (archived).
Adultery was not a crime in South Africa in 2025. Additionally, following a 2015 Constitutional Court ruling, people there can no longer sue for damages (usually monetary) based on adultery.
'Arrest' and 'sue' mixes civil and criminal law
Aspects of the claim text that was shared via screenshot also cast doubt on its validity. After the claim said that cheating would be "illegal," it went on to say that, "You'll be arrested for violating a contract" and that people could be arrested or sued if their partner had "enough evidence" a partner was cheating.
In the U.S., police can make an arrest if they have probable cause that a person committed a crime. The Constitution's Fourth Amendment protects "persons, houses, papers, and effects" against "unreasonable searches and seizures."
However, breach of contract, which the term "violating a contract" in many of the claim examples likely refers to, generally falls within civil law in the U.S. In the civil law system, plaintiffs can sue defendants for damages, usually in the form of money. A lawsuit starts in the court once the plaintiff files the case, and arrests aren't generally made unless the case also involves a crime, such as fraud.
U.S. state law generally governs marriage. In terms of federal legislation, the U.S. Code defers to this — if a marriage was entered legally in a state or could be entered legally in a state if it was entered elsewhere, then it is also valid under federal legislation.
However, marriage is not a traditional contract that would fall under contract law. A marriage license or certificate does not generally lay out a promise to stay together — rather, the documents indicate that two people are eligible to be married (license) and that they have been married (certificate). For there to be a breach of contract, there would have to be terms to breach. A marriage certificate contains no such terms. This may be different if couples have entered into prenuptial or postnuptial agreements.
Given the above, under U.S. law, people generally cannot sue a partner for breach of contract if their relationship breaks down. It is possible in some states to sue specifically for adultery or report it as a crime. More on that below.
Adultery in the US
In the U.S., adultery is a felony in some states and a misdemeanor in others. In a small number, alienation of affection allows individuals to sue a third party if that third party caused the spouse to lose affection for the other spouse.
Adultery was a felony in 2025 in Michigan, Oklahoma and Wisconsin. Adultery in Oklahoma carried the highest potential prison sentence of up to five years. The highest possible fine for adultery was up to $10,000 in Wisconsin.
The following 13 U.S. states classed adultery as a misdemeanor in 2025:
- Alabama
- Arizona
- Florida
- Georgia
- Illinois
- Kansas
- Maryland
- Mississippi
- North Carolina
- North Dakota
- Rhode Island
- South Carolina
- Virginia
Adultery was also a misdemeanor in Puerto Rico.
However, though adultery was a felony or misdemeanor in some states, law firms in Michigan, Oklahoma and Wisconsin, where adultery was a crime, generally said police and courts rarely enforced the statutes.