Don't do it. I've been on the receiving end of shit like this in the past. I was once good friends with someone, we were pretty cool, and him, me and my then-gf would hang out together and have a good time. Then my life started falling apart, I dropped out of school, a close family member died and me and my gf split. At the time, my "friend" didn't do much for me, and told me to just get over it.

So when I got a new job about a year ago, I saw this old friend of mine and I wanted to catch up on things. He seemed a bit weary of me and I couldn't figure out why. Found out from another old classmate that he and my ex had been together for about 2 years and had said quite a lot of shit about me. You don't know how much I want to smash that guy's skull in every time I see him, but I keep myself under control.

The guy's an arse anyway, but the fact that he dated my ex only a couple of months after we split enraged me so much. He wasn't much of a friend, but if you value your own friendship, then don't do it. Girlfriends come and go, but your friends will always be there for you. Don't fuck everything up over a girl.