My wife was talking to a friend of mine(without my knowledge) every day on the phone and then cheated on me?

We went to a party at his house and they were both flirting with one another and then all of a sudden she goes inside the house from the barbecue and he followed her.I thought that something was going on so I followed in a few minutes later.What i discovered was that they were both upstairs.I wasnt sure if anything was going on so I waited downstairs to see how long they were up there and if they came down toghether.5 minutes later they both came down stairs and I could tell from the sneaky looks that they were giving each other that something was up.So on the ride home I called her bluff and told her that i heard her screwing around upstairs with him and I didnt want to make a scene.Sure enough she then confesses but says he forced himself on her.Would you believe this story ???