I agree, calling yourself a Unicorn implies a lot more than a single, bisexual female who wants a relationship with a couple.
Often it adds in an *exclusive* relationship where the couple stays dominant and only is with the single girl when it suits them. They make the rules, and the single girl is expected to live by them.
Yes, that's the stereotype, but you see it all too often, I'm afraid.
"Listen, or your tongue will make you deaf." - Native American Proverb