Joe, I want to add a comment to the advice you've already received. One of the reasons people stray is because it seems easier than fixing what needs to be fixed in the marriage. It's exciting to think about someone new. But it's been said already that newness wears off and you will be back to square one. Most people regret their decision to leave a marriage for another person within a relatively short period of time.
I think it's great that you've cut off this relationship and it's natural for you to think about that woman. Think about her all you like, just don't act on it. You don't go from intense fantasy to cutting off all thoughts about the OW overnight. Not if you are normal. So don't worry about that, thoughts of her will fade as your marriage improves and your moral compass re-emerges. Obviously, you want to do the right thing and you are on the way to doing that.
It's going to be hard for your wife. Not only did you betray her, her best friend did as well. That's a double whammy and you are going to have to be very loving and patient with her if you want your marriage to work at all.
Do yourself a favor, figure out what you need to change about your marriage to make it more exciting and loving. Go to a SBT therapist to get things straight. Read DB.
And one last thing, I hardly believe that group sex would be an answer to your dilemma. I think it's bad advice. I would have to guess that you already knew that.
