Okay, okay..., somehow the term "unicorn" has been given definition. A "unicorn" is a "hot bi babe" who is single and polyamorous... and elusive--, one supposes, mainly because she's expected or desired to love both members of a "straight" couple..., in which at least the female member of said couple is... --you got it, bi.
But hold on a minute!
How do unicorns continue to exist as a single-sexed species?
Let us imagine two queer guys, also bi, who are a couple. These do exist, no? Let us further imagine that they are considering opening things up to a third in a triad situation.
Or let us imagine two queer women, also bi, etc....
Why are these elusive animals thereby nameless?
provide them with a name?