Definition of polyfi / polyexclusivity / polyfaithful

“Polyfidelity (also sometimes called polyexclusivity) is a form of polyamory where all members are considered equal partners and agree to be sexually active only [or mostly] with other members of the group. …

Polyfaithful relationships are, like monogamous relationships, closed in the sense that partners agree not to be sexual outside the current members of the group. The difference is that more than two people are included in the closed group. …

One might think of polyfidelity as being… like monogamy with more than two people.”

– https://en.wikipedia.org/wiki/Polyfidelity