I just went back read your original posts, and I didn't see you two getting to the root of the EA. NOPkins is right, the situation is f**ked up and needs to be thrashed out. IMO she is back out of guilt and lonelyness rather than any real desire to fix the marriage.
You have my sympathy, I don't have much advice on how to proceed, other than addressing the problem directly is usually the best approach. It's hard to do with a loved one though.
