Polyfidelity

Polyfidelity is a form of polyamory in which a group of partners are committed exclusively to each other and do not seek additional partners outside the group. It is sometimes described as a closed polyamorous relationship. A polyfidelitous group might include three, four, or more people who are all romantically and sexually involved with each other but not with anyone outside the group. Polyfidelity combines elements of monogamy (exclusivity and commitment) with polyamory (multiple partners within the group).