arousal

The term “sex addiction” is used to describe a pattern of frequent, progressive, and often secret sexual behavior, even when the behavior jeopardizes a person’s time, employment, financial stability, relationships, and reputation. While often conflated with adultery, sex addiction does not necessarily mean cheating—or even intercourse. Rather, it can manifest as a dependency on pornography, masturbation, phone or Internet sex, and other related behavior.

Sex is over when one or both partners don't want to have it anymore, either because they both feel satisfied or just because one or both are done with the whole works for the time being.