I guess that since I'm just an old fart and still consider things like "trust" and "loyalty" to be a part of friendship, I'd X the guy out of my book.
"Someone who opportunistically snakes something out from under you, that you really wanted, and he KNEW you really wanted it."
I wouldn't leave him with your girl, either, if I were you.
Of course, if you don't require your "friends" to be trustworthy, or to be loyal to you, or have any sense of ethics, then BY ALL MEANS, keep the friendship.
Everything said here is pretty much exactly what I was thinking. ESPESCIALLY this statement.