Polyamory is motivated by a desire to expand love by developing emotionally involved relationships with extramarital partners. Swinging is motivated by a desire for physical gratification by engaging in sexual activities with extramarital partners.

The distinction between polyamory and swinging has recently started to appear in academic publications:

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.

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. New members may generally be added to the group only by unanimous consensus of the existing members, or the group may not accept new members.

The word “polyamory” is based on the Greek and Latin for “many loves” (literally, poly many + amor love). A polyamorous relationship is a romantic relationship that involves more than two people.