A partnered character sneaks around for sex with someone else, whether it is a secret affair behind their lover’s back or getting caught mid-fuck. The scenes usually lean into guilt, betrayal, and the thrill of doing it somewhere risky, and they often end with a confrontation or a jealous, humiliated partner. Sometimes it overlaps with cuckold setups where the betrayed lover is forced to watch or finds out after the cum-stained evidence shows up.