I found out today that my best friend of several years has been dating my girlfriend behind my back not soon after she broke up with me. I don't even know what/how to think of this I didn't even know people could drop so low
so he's not actually dating your girlfriend, he's dating your ex-girlfriend? big difference there. still kind of a dick move, unless you told him you're ok with it.
Hate to inform you....but that that is not your best friend....so let them have each other. Find someone better for you....don't settle for crap.
Um ... what's the issue? He didn't make his move until after you'd broken up with her. Well ... that was gracious of him. But if he's been politely biding his time, rather than making a play foe her while she was your current rather than your ex ... why SHOULDN'T he make his move once she's your ex? It's kinda inherent in the concept of an ex that they're free to see whoever they choose, ya know?
I wouldn't be too upset unless of course she does things with him that she refused with you? is she giving him poop chute access? blowing him in the car? bringing her girlfriends into the bed? no? so who fucking cares.....he stopped being your best friend the second he decided to not tell you like a man have you considered killing both of them?