Welcome to the best place to be during this emotional chaos.
One very helpful book is "Not Just Friends". It's invaluable in describing the feelings and motivations of the cheated partner, the wayward partner and the other person. It also contains a framework for moving forward with reconciliation.
How do you stop endless questions to her? Focus on yourself. Go to counseling. Learn what healthy boundaries are and institute them. It takes time. For now rely on your bullsh!t meter. If something seems wrong, it probably is.
The only person responsible for their happiness is the one they see in the mirror. AA provides a framework for dealing with the disease and incredible support within the group. It's good for her that she's going back. How long was she gone?
Have you read "CoDependent No More" or gone to Al-Anon meetings? Couples often have that dynamic of one of addiction, the other with codependence. Find a support group for you.
I'd tell the friends you trust who are willing to do more than just console you.. those with life skills and experience to broach these difficult subjects. Those friends who hug you but are willing to swing a 2x4 as a reality check.
Your significant other has a support group in place with folks who will ground her in AA. It's important that you develop one for yourself. Work on you.. and the rest will follow.
