If the people in her group found out, her world would crumble to nothing. She would basically see her life as being "over." The OM would probably be kicked to the street; maybe not. But his business would come to an abrupt end and his reputation would be ruined. I've really struggled with not exposing the A. The main reason is that it gives me leverage. In the event of a D, then she can have the life that she wants but then I get what I want: primary custody, child support, and not have to give up any equity in my company. Those things are the most important thing to me. That "leverage" ensures that I get what I want.
You are doing a great job of taking care of yourself. Don't just detach and work on yourself physically. Focus on your mental too. None of us are perfect. What do you need to do to be a better person? What skeletons do you have in your closet. Spend this time making yourself a better person.
Also, detaching isn't about ignoring her. Its clear she's hurting. She seems to be truly remorseful. That's the first step towards reconciliation. Its ok to respond to her if she texts or calls you. Just don't be the one to initiate. At least not yet. And it probably wouldn't hurt to make her wait a little bit when you do respond. Make her squirm a little. This isn't about punishing her. Not if you truly want to repair the damage she's done to your marriage by the A. If she's remorseful, you have something you can work with. Get her to go to IC. You should go too. Then you can work on MC.
I really hope the best for you. It seems like she might be in a place to be wiling to repair the damage she's done. I WISH my W would express some remorse. But I got nothing.
Me: 48 y/o W: 47 y/o Together: > 20 yrs BD: Dec '15, then S 2nd BD: Mar '16, then I filed for D April '16: started piecing