Multigamy
Multigamy is the broad term that covers all types of relationships that involve more than two people.
Multigamy is a newer and more encompassing term for ethical non-monogamy or consensual non-monogamy. Both of these terms pin an identity as being "other" to something else, rather than a distinct identity in its own right.
This includes polyamory, swinging, and relationship anarchy.
Multigamy is portmanteau created by
It’s a term I coined to replace ‘non-monogamy’ as the blanket category of all non-exclusive, multi-partner relationships.
These are some broad categories that are helpful to understand.
For a more complete picture of all the ways you can define your relationships, check out this graphic.
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Source: The Map of Non-Monogamy