This is what you get when you stay with a cheater. 

The only advice is the best advice. Get somewhere where you never have to hear that BS ever again. 

You should have asked your wife what did she think you would get from that statement and why does she think you want to hear about the sex she had with the other guy?

I'd take it as she is trying to be completely honest with you and not want to lie or hide anything. There is probably some guilt over everything coming out and she feels the need to confess every detail. 

If you don't want to hear or know it, tell her that. It's understandable why she would feel compelled to say something. It's understandable why you wouldn't want to hear it. So talk over what the boundaries are and what will help you move past it versus what will hurt you more.

If everything else is going well, don't let this be the thing that destroys it all. Remember, she isn't with him. She isn't with anyone else. She choose to stay with you. As long as you are both working together to heal these kinds of words, then it's good to not think about him and let the past be the past.

Oh, and while she may have learned something from him, you are the one that now gets to benefit from it. That puts you ahead and the winner here. So enjoy her newfound skills.