If you have health insurance call their pschiatric or mental heath division, tell them your situation. They usually assign a councillor and might have special crisis workshops. Second if you dont get a councillor that way find a therapist who specializes in relationships.
There is also midfullness-stress reduction workshops.
I reccomend techniques like breath-work also know as rebirthing.
Try this go some where private and alone, Mabey in your car( you might want to park), think of the things that make you mad about this situation and let out your anger out. You can yell scream, use any language you want and PURGE that anger. Check out http://www.al-anon.alateen.org/ and go to a meeting(you dont have to be affected by alcahol to get benefits from this. Check out http://www.slaafws.org/ these are great places to get personal(free) help.

These all helped me in my life, especially when I found out My ex-wife was a prostitute. I felt so much confused rage,I decided, whateverI did to attract this person into my life, I needed to change that. So I went to work on myself and did alot of hard work.

Remember, there is no way through this except through it.One day at a time (or minute for that matter) Its hard to see any positive in a situation like this untill later, but, Use this as a positive learning experierince. If I got through my experience and survived and became better and happier, Im sure you can too...If things look really bleak call freinds, family, hospuitals, or the samaritans, dont isolate!!!

Hang in there. Remember this most of all. Nothing that happens to you is EVER bigger or more important than you are!!