First thing first you need to go to marriage counseling with your wife. If there are issues and she really does want to work things out she will do ANYTHING to do it.. if she doesn't want to go to marriage counseling the next step I would take is getting a lawyer because she obviously doesn't want to work things out. Regardless of all of this I would also hire a PI to see what exactly she is up to from day to day. Some people say this is distrustful, but she has lost your trust as it is and has no reason to be trusted.
I would not hesitate on doing any of this either. I would suggest maggiage counseling in the next day or so. Also visit this site..
www.marriagebuilders.com and check out their forums. They have lots of good information and people to ask questions and should have some great advice.