I went to a mates house 2 nights ago for a sleepover and then a hang out yesterday, and his friend's (a friend of mine too) ex-gf was there as well as him. We got along pretty well and I've got her number, but would it be slack and wrong if I made a move on her, they're only recently broken up. I really want to, but I also don't want to seem like a dick.
Don't date behind there back, because once he finds out, you'll wish you wouldn't have, I've done it before. In the end, it's not worth losing a good friend for a girl, unless you are really in love with this chick. I almost lost my best friend I grew up with since the age of 4 and I cried a few nights a few years back. Honestly, let your friend know you like this girl, it's best you both know about it and are both level headed about it.