It's the man's rules. You can't tell on him. Don't do it, PD. That'd be fucked up. Don't effin do it.
Okay, go ahead and tell. Break ups are always funny. Oh and realize this, the girl will hate you by association. It always happens.
Still, if it was me, I wouldn't tell... unless I wanted to get a good laugh. Oh fuck it, just tell. But the girl will hate you, realize this. But shit, it will be pretty funny. But dude, guys don't do that shit to other guys. Haven't you seen Old School? But fuck dude, I always found break ups hilarious.
I hope this helps.