some good points from John and Ryan, but I will still say friends and another pussy (or mouth) to put your dick in is the only thing that will make getting over this bareable. Just rememeber to lose her number.
I still think you should fuck that dude's mom... He's a tool, if they work together, odds are he had to know she was involved with someone so he's just as guilty... anyone that says, he's not just as responsible is stupid... part of being a man, is manning up and not sticking your dick in someone else's koolaide.