Billet-Doux: n. (bĭl'ā dōō, or "billa doo") A love letter. (literally "sweet letter" in French)

So, you have your friends and then you have the people who you think are your friends. Those people are called “frienamies.”

Urban dictionary defines a frienemy as someone who pretends to be your friend but really isn't, as in they turn on you.

Let’s face it, we have all been faced with fake friends. Hell, I'll be the first to admit I have been one. I committed the biggest sin of all in a friendship.I slept with my so-called best friend’s man. And not just once.