I am so sorry you are going through this. But listen, it's never going to get better. They are sneaking around. I am assuming the only reason you found out was because she got pregnant. So now you are most likely raising someone else's baby. I hope you have proof that he actually donated sperm and not hooked up. Anyway, keeping a secret like that in the first place is a total deal breaker. Why weren't you involved the pregnancy process. Kinda odd that you were left out of that. She is trying to manipulate you into believing for the baby's sake that this man needs to be in your lives, but hide it from his wife?? No way dude. Oh and poor me, I was going through a lot...please we all go through a lot, getting pregnant is not how you solve a problem...that is just a lame excuse for her deceitful behavior. Why hide a friendship from his wife unless there is something to hide? 1+1=2, something is not adding up. Have you talked to a therapist? If not I think you should...sort out your feelings, and find out why you allow her to treat you like this.