Dazed, First time I've posted to you. I'm a strong supporter of exposure. It's a tough call.
Maybe I can share something from my sitch and see if it helps.
After I found out about my WW's affair, things were tense for a while (understatement there). I decided I was going to be the best husband I could be so if we did separate I could go dark and she would remember me in the best light and if the affair ended she might come back.
I think my WW took my being nice as my condoning her affair. When she was around me it was like we were best buddies, but she would always run back to OM. We even went to Fla together with 2 other couples and had a GREAT time, but of course she would sneak off to call or TM OM every chance she could. I even saw some text messages between them on the trip where WW was telling him she was having a great time and OM ripping on her because he was jealous of his mistress having a good time with her husband. I thought for sure that after having a great time with WW she would come around, but the first chance she had after our trip she went and spent the weekend with him. She was planning another weekend trip to see him when I exposed to his wife (I kind of goofed up that weekend for them!).
Point is, my WW was a cake-eater deluxe. She was getting most of her needs filled by me and a couple from him. So heck yes, she'll say she has good feelings for you. You're letting her F her boyfriend without getting in the way. She contacts you when she needs her fix of you and then gives the buffet to her OM.
Break the stalemate. Find a few people who exposing to will have the greatest affect. The other persons significant other, parents, close friends. Family may sympathize with you and support her, but frame it in a way that you are trying to save your marriage and would like their help.
I'm not trying to convince you to do something that you don't want to do. And there are many people on this board that disagree with the exposure route, but it's seemed to work for me and many others here and elsewhere. If you don't want to expose, go dark. Cut off all contact with her. Tell her that it pains you too much to see/talk to her while she's still with the OM. And stick to it if you do it. If she comes back, great. If not you've at least removed the continued pain/limbo from your life.
It's your choice.
Hope4us
Me - 49, W 49 S22 & S18 Dday 9/4/07 W claims NC 4/7/08 8/29/09 - Divorce Busted. Lots to work through, but we're going to make it.