Do not leave the house. I don't know where you live, but it could be taken as abandonment and that is the last thing you want as it could give her grounds for divorcing you. You can ask her to leave, but unfortunately she doesn't have to. If you have the money, consult a lawyer immediately. I'm going through a divorce and I fled the house for fear of my life, now he's trying to get me for abandoment. How long have you been married? I wouldn't confront her. You know how she feels about you and nothing good would come of it. I'd start keeping a file on all information you've gathered in a safe place. Try to see what else you can find that will show that she cheated. Until you've spoken with a lawyer, I would act like you don't know anything.
Good idea about consulting your friends on your behaviour. Just don't get defensive about it if they say you are. We all have problems with our behaviours and until we learn about them, we can't change.
Please feel free to contact me if you want to! Sorry this is happening to you!
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Man is fond of counting his troubles, but he does not count his joys. If he counted them up as he ought to, he would see that every lot has enough happiness provided for it. ~Fyodor Dostoevsky