Believe me, as my H has had two ow, I know how horrible coming face to face with the actual truth can be. Give yourself permission to be upset and feel like crap because frankly it sucks.
Then, take a deep breath. Keep yourself occupied and perhaps pull back from your W a little until you sort out your feelings. I don't think the hurt ever goes away, but it will get better.
In a way I think this might actually be good for you. For some time you wanted to believe it was not a PA and this will force you to deal with your feelings instead of clinging to the possibility that it wasn't true.
Whether you discuss what you found with your W is really up to you. Sometimes we all walk around on eggshells for fear anything we do wrong will send our WAS even farther away.
The fact that your W thinks she may be pregnant is perhaps one reason she has been reluctant to rekindle a physical relationship with you. I know this probably doesn't make you feel any better, but at least your W will not find herself in a dilemma over the paternity.
Remember, your W is probably under a lot of stress as well. It is possible that she was still sleeping with him even after her feelings changed. If he was violent toward her and is giving her grief about trying to repair your M, it's also likely that your W felt pressure to continue the physical side of things even after her heart wasn't in it anymore.
Take care of yourself GH. This is horrible information to have thrown at you at a time when you thought you were slowly making progress. (And really I think you still are.) Try not to make any decisions or confront your W until your initial feelings subside and you have a little time for your head to clear.
