Definition - What does Multipartner Relationship mean?
A multipartner relationship is a relationship where the participants have more than one sexual and/or romantic partner in their lives at any given time.
Kinkly explains Multipartner Relationship
There are many different formats a multipartner relationship can take, from an open marriage where the partners date to a group marriage where everyone is committed to each other to a triad where two people are both committed to one central person and many more. There's not a "right" way to have one.