I searched this morning for communities related to polyamory and open relationships. Finding nothing, I created something. If you are interested in polyamory, open relationships, ethical non-monogamy, etc, swing on by for a chat, to post something silly, as you will.
edit: !polyamory@kbin.run
Polyamory’s for lesbians too. Three women all dating each other counts. In a different comment they talk about not knowing what polyamory is, looking it up, and getting sex stuff, so maybe they saw some one-guy-two-girl porn stuff?