Sorry you are here buddy. This is a rough path to go down but you CAN come out the other side a better/stronger person.
First, believe NONE of what she says. A sticky note saying she has ended it with OM is NOT enough to prove that she is no longer a WW. In fact, I can guarantee that she is still wayward. No doubt in my mind. You've got to see her hit rock bottom and express true remorse before you can even begin to start trusting her again.
My advice is to detach, 180 and GAL. Most important is the detaching and it is the hardest. Right now, you've essentially got to mentally leave the M (because she has) and put all of your focus on you. If she's had multiple A's, she has some serious issues and only she can fix that. You can't. Spend this time working on you and do your best to forget about her. Let her sit in the mess she created and figure out what she needs to do to fix the situation. Do NOT be too quick to take her back. This will take a lot of time. Much longer than you think it will. Find a path forward that doesn't include her. I know it sounds backwards but when she sees that you are willing to move on without her AND show her that you life is better without her, she will see what an awesome H she is losing and it will help drag her out of the fog. I don't possibly see how it can work for her to continue working with OM. For me, she would need to get another job or at a bare minimum, move to another department where she can't have any contact with him. Do not initiate R talk. I would go LRT so long as she is still wayward, and again, she IS.
If she is going to end it with OM, she needs to send a letter (which you help write) or make a phone call in which you are listening to. She needs to be very clear that the R with OM is over and that there is to be no contact ever again. There also needs to be a transparency plan in place where you have access to all her emails, texts, etc. The "encrypted" apps need to go away.
But I think it is premature to even begin discussing these things. She is still wayward. She is in NO position to ask you what you want and then in the same breath tell you that she may be willing to not comply. That's BS. You and you alone get to decide the conditions of R. You MUST be firm with her.
