Whenever polyamory and monogamy coexist in the exact same relationship.

Like other mixed-orientation relationships, poly/mono or mono/poly relationships include people with differing identities or practices—in this instance, one monogamist that is intimately exclusive with one partner, plus one polyamorist who may have or is seeking numerous lovers with the data and permission of all worried. The relationship is poly/mono, and from the monogamist’s perspective it is mono/poly—either way, it means …