A relationship that allows behavior, affection and sexual expression with partners external of the relationship. The most common forms of non-monogamy are swinging, open relationships, and polyamory.
Non-monogamy is different from cheating since all of the involved parties are aware and consenting of the activity occurring outside of the relationship.
Responsible Non-monogamy will often occur in mature relationships and is different from standard non-monogamy. A relationship that is engaging in responsible non-monogamy will have explicit rules and conditions which must be adhered to in order for one of the partners to pursue sexual behavior outside of the relationship. A common condition of responsible non-monogamy is a ‘condom contract’, wherein sexual protection during intercourse outside of the core relationship is mandatory.
Larry: “My wife and I invite other people into our bedroom at least once a month, we’re non-monogamous.”
Jack: “Nice where is my invite, haha. Just kidding.”