Swinger

A person who has consensual sex with other people within and outside of their committed relationships. This is a respectful dynamic that, depending on the relationship, works in different ways for different people. There are often boundaries that are pre-negotiated between swingers such as who is able to sleep with whom.

There are more than 112,000 people on FetLife who have tagged themselves as swingers in their profiles. The site also includes more than 1,900 groups devoted to swinging.