This may represent independent coinage of the same term within a different community, and this usage is not common among polyamorists in general.
After that is the secondary partner, which as the title suggests, means they get less time, attention, and commitment than the primary partner. You might be wondering: What’s the difference between an open relationship and a poly relationship? The main diff, according to the Poly Coach website, is that in an open relationship, there is always a primary partnership. In a poly relationship between three people (known as a triad) everyone could love each other equally, with no favorites.
In an open relationship, there is a committed couple at the center.
Polyfidelity (also sometimes called polyexclusivity) is a form of polyamory where all members are considered equal partners and agree to be sexually active only with other members of the group.
The term originated in the Kerista Village commune in San Francisco which practiced polyfidelity from 1971 to 1991.
The community expected all of its members, within bounds of gender and sexual orientation, to be sexually active with all other members, and for exclusive relationships not to be formed.
However, this aspect of polyfidelity is not always expected today.
Some polyamorous people also report that it is difficult to find partners who are mutually compatible enough to form committed group marriages like polyfidelity.
In the book Lesbian Polyfidelity, author Celeste West uses the term polyfidelity in much the same way that others use polyamory.
Some polyamorous people desire more flexibility than polyfidelity provides.