Swinger
A person who engages in the Swing LifeStyle. Also known as a LifeStyler, Swingers are people who partake in group sex , one on one hook-ups or the swapping of sexual partners. Swingers attend or host Swinger/Lifestyle Parties.
It is for open sexual personalities and like minded individuals.

Although many Swingers enter the Lifestyle together, there are plenty who enter the Lifestyle as a bull, a single man in the Lifestyle who plays with other people’s wives and a unicorn, a single woman in the Lifestyle who likes to play with couples. There are also Nymphs, and Rexes. A Rex is a single man who enters the lifestyle and plays with women who are single or attached, REX means King. A Nymph is a straight (or bi) single queen who plays with men in the Lifestyle.

There is no room for jealousy or dramatics in the swinger realm.

Swingers are everyday people with jobs or lives just like everyone else can have. They are people who are very comfortable in their skin looking for new, exciting ways to explore their sexuality. There are voyeurs, exhibitionists, bdsm kinks, poly relationships and couples looking for the third, plus other types of swinger sub categories.
Some stumbled into the Lifestyle because they were bi-sexual or bi-curious, some for the desire to have sex beyond pro-creation and many for relationship excitement, some through marital issues, which in most cases, ended up enhancing their communication and relationships (if done right).
My wife and I wanted to play with other couples so we went to a Swinger Party.
I am a Swinger.