Adultery
Adultery is extramarital sex that is considered objectionable on social, religious, moral or legal grounds. Which sexual activities constitute adultery varies, as does the social, religious and legal consequences. In the US, laws vary from state to state but it adultery remains a criminal offense in nearly half the states, although prosecutions are rare.
Here on LawServer you’ll find relevant state laws about adultery, and related legal Questions & Answers.