ok, first... you are getting the standard script. I'm sure you've been browsing this board and may have noticed some of it.
Regarding the OM as you talked about in the first post, understand that it probably has nothing to do with money. Also, unless you really know this guy, he could have been lying to your W about his own "marital problems". Finally, good you didn't confront him. It might have felt better in the moment, but it could end up a really bad thing.
It's time for you to really get down and do the work on yourself. The A is just a symptom of something else that's not working in your M and that is due to TWO people, not just your W and not just you.
You've let your W know in no uncertain terms how you feel about her R with OM. Having let her know, it is time to stop that. It is unlikely that she will forget or that you were unclear. Beating that horse will not help and may do more harm.
If you are going to do the "tough love" with your W over the A, then you need to enforce your boundaries and dish out the consequences. If the boundaries have no bite, then they are useless. But DBing isn't about controlling our spouses...
Most of the resources on DBing is strewn about this forum, but I do not see that you indicate you've picked up the books. We recommend getting the DR book for sure which is the more recent one that really puts a lot of this into a functional style of how to DB. The first book is great as well, of course.
What do you know about LRT? And how about GAL and 180s?
As the A is a symptom of a deeper M problem, what are some of the things that your W complained about, BEFORE the A and the bomb?
When do you feel things started going downhill in the M, prior to the A? What were some of the things going on? Stresses, family issues, etc???