A unicorn is a mythical beast with a horn 😉 It also refers to a pretty and otherwise dateable bi female who is willing to date a couple. A lot of women are sort of okay with poly, but only if “we share”, making it really hard for the guy to find someone. I mean, what are you supposed to say? “Wow, you look really interesting, can I bring you home to meet the wife?”
Unicorns are easier to find in poly circles or swinging circles, but not MUCH easier; it’s hard enough to find a great girl to date when you are single, much less when you have a whole laundry list of added requirements. So that, my friends, is a unicorn.
Here is a GREAT website dedicated to Polyamory.