Polyfidelity

Polyfidelity, a form of polyamory, is usually thought of as the restriction of one's sexual activities to a single group of people, each of whom follows the same rules and has sex only within the group. This term originated within the Kerista Village commune in San Francisco which practiced polyfidelity from 1971–1991. Polyfidelity has also been practiced in other cultures and times.

Previous to the Kerista Village experience, people spoke of "group marriage". The term "polyamory" or "polyamoury" was coined much later, in the early 1990s (see polyamory).

A closed, "mutually faithful" polyfidelitous arrangement offers the same health advantages with respect to STDs as monogamy if the usual tests are undertaken by each person within such a circle, although the risk rises slightly with each person added, until their disease-free state can be verified.