Hi caughther,
I would caution restraint, at this point. I don't think you should follow her or treat her roughly or the least bit abusively. It would be great if you could post some portions of the audio so we could hear the sort of things they discuss while fucking, but I don't think you should change anything right now in your relationship with your wife. Remember, she does not know that you know. At some point, the affair will grow old and, hopefully, he will be the one to dump her. When that happens, she will still have her secret but will feel like the kind of woman you clearly want. At that time, she will be yours to use as you like. But, until then, any changes by you or any rough treatment may just move her closer to him and away from you.
I truly think that you are going to really love the aftermath of this affair but only if she can think it's a secret. Your wife and her lover are, most probably, doing things that she had never done with you. Eventually, you are going to benefit from the experience that he is giving her. And... You get to fuck her with the knowledge that she learned new tricks from another man.
You have a Compersive husband's dream going for you right now. Don't blow it by treating her like a slut. That is for her lover to do. Your wife is not a slut, of course. She's merely a wife who is seeking sexual satisfaction from another man. Let her have it and let it run its course. You should just jerk off a lot more and think about them together. Once the affair is over, you can change things but, for now, leave her be and enjoy the ride. Travel more so she can bring him to your bed and, by all means, please post excerpts from the audio sessions. We would all love to hear some of it.
Good luck with this, my friend. Keep us updated.
Lance