I'm having a cocktail party and inviting a polyamorous friend. I'm inviting her legal husband, whom I barely know but he is her husband. He has a lover that they seem to hang out with all the time whom I went to high school with, so I invited her.
My friend has another lover who, judging from his livejournal page, is oddly obsessed with elves. He's "otherkin" if you know what that means. I don't know the guy and have trouble believing he would gel with the rest of my friends, though that may be my own speciesism against elves showing.
I realize that when one invites people to a party, one is supposed to invite their significant others.