Listen, your WW reality is different from yours. In her reality she was dating this man and in a relationship. You might not like it or want to hear it, but it's her truth.
Why do she want to go to counseling? Why did she tell she wanted to go? If she hasn't told you ask! Most likely it's for her own justification. It's a selfish move on her part, to lessen the burden of guilt. She has a lot of shame to deal with and anything that can help minimize her guilt she will try.
Lastly, you don't have to Divorce to get to where you need to be. But you do need to work on your healing. It's your choice to allow her to bring you into fights and arguments. It's your choice to listen to her vent to your about her relationship with the OM. Instead of telling her you don't want to hear about him. What actions can you take when she brings him up? One thing you can do is say, "I'm done with this conversation and walk away, every single time she mention his name or reference their relationship", and I mean every single time. She will get the message.
Stop putting all the burden on her to help you heal and respect your boundaries. Come up with tangible actions/consequences to her disrespect and hold her to them. Stop being afraid of her reactions, and learn to respect yourself more than her reactions.
Joejoe
I have asked why she wants to go to counseling. Her response is to work on having a better relationship. Not necessarily to save the marriage. I know that counseling will be only for her to justify why she was having an affair and to justify that she believes I never truly loved her. Maybe to convince me I would be better off without her. These are things she has told me in the recent past. So counseling would be more for her justifications than it would be for me. I do believe that her respect and idea of me is so low that she feels like counseling will also help me not be angry about the split.