Adultery isnt just a crime in the eyes of your spouse. In 21 states, cheating in a marriage is against the law, punishable by a fine or even jail time. States with anti-cheating laws generally define adultery as a married person having sexual intercourse with someone other than their spouse.

What is it called when you sleep with someone while married?

The definition of adultery is thought by many to be in need of a serious review. At the time of writing, the legal definition of adultery is a married man having sexual intercourse with a woman other than his wife or a married woman having sexual intercourse with a man other than her husband.