Dont sweat it. Stay tough, and they'll leave you alone. Money over b*tches dude. If you messed with his money, his boys would back him, but not over a ho.
If he comes to you over it, just tell him that if it wasnt you, it'd be someone else. In the long run, he'll understand that she punked him, not you. If she was his b*tch, she had a responsibility to him. You didnt.
Fvck him, it's his deal to get over, not yours. My advice to you though is stay away from this dirtbag chick, unless you feel good about stirring a bowl of other guy's chowder.