Okay, first of all: Im sorry. You did not deserve this.
But are you absolutly sure about this? You don't want to make assumptions without some sort of evidence.
If you are sure, you probably have tendency to maybe hurt him, yell at him, cry your eyes out and show him how much he hurt you. When you feel like this, it might not be a good idea to talk to him. I mean, you are husband and wife, so even though he did this to you, doesn't mean your marriage is over.
It doesnt sound fair and it isn't, but you have to be the bigger person now. If you are calm, go to him. Go talk to him in a serene way. No attacking or something. Tell him that you know he did something and that it hurts you deeply. If you do it like that, he knows you are not mad (even though you are, but you can express that later) and he might be able to just.. Talk about it. There is of course no excuse for it, but this is better than just to throw him out or shut him out. Good luck. I hope it works out.