Must be the season for it. I just found out my wife's been having an affair. Then within a week two of my friends broke up with their partners (both long term relationships). The up side is that we're all bachelors again and can hit the clubs again, the down side is we're all bachelors again and don't feel like hitting the clubs. I feel your pain and am sorry that you have to go through it.
I think andronicus and biomech both give great advice. No point carrying a grudge it doesn't solve anything. And you can only move forward so use this as a learning experience and when you come out the other side you'll be a better and stronger person for it.
Good luck, and remember, if this is the worst thing to happen to you then you're still doing ok.