In your update post you gave about the R talk, you started several sentences using "she admitted". Just to clarify, were you asking her these questions where she confessed (maybe reluctantly)....or did she volunteer the information?
When you describe the talk by saying she admitted certain things, it concerns me that you may have pressed for her to agree you were correct about these issues. The reason I bring it up now, is b/c if the discussion was closer to you drilling her and wanting the personal satisfaction that you were right about all of this all along, then I worry about her level of commitment. And let's face it, she did seem to say that you did all the right things and everything you previously thought were all true. I just thought her words sounded too much like the words you had told us a long time ago. But maybe it was b/c you were paraphrasing.
This is not meant to be a 2x4, SM34, but I'm just hoping that it was all her freely telling you this without any pressure or assistance from you. And, you do tend to want to think and talk for her. If you were asking questions that prompted her admissions, then her level of commitment may not be as deep or she may not be as eager to commit as she would if she told you these things without being quizzed. Does that make sense?
I'm not saying you shouldn't ask questions. I think even MWD says the S who had the A should be willing to answer questions in order for them both to heal the MR. But just speaking from my own VP, I hope you won't have the need to ask a lot of questions about OM and the sex stuff. B/c it places a lot of focus on him. The more details you know about everything they did (especially in sex), the more you would have a hard time forgetting. I have read where people have regretted knowing too much. Several have asked and then wish they could get the image out of their head. Don't make this about him and her, but rather make it about you and her.
The real issues you need to focus on are the problems that were between you two---that caused her to reach out to someone else. Keep the subject matter on the two of you and don't bring the third party into it when you are trying to heal. Everyone won't agree with that advice, it's just my viewpoint.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!