Jason.......I can understand how you must be having lots of feelings of uncertainty, right now. Worrying about things that you may have no control over.
Uncertainty about future unknowns is a very hard thing for us humans to deal with.
For the immediate---I agree with Dee's idea of trying to back away and give her as much space as she is askin for.
Try hard to not "future trip".
I don't think you are being selfish, at all. You are entitled to your own feelings.
My suggestion is that the very best thing you can do for yourself is to line up and engage as much support for yourself as you can. Your wife is surrounded with support for herself---and, she will have it when she leaves rehab (if she uses it).
A. sometimes, fact that gets ignored is that the non-alcoholic partner needs as much support as the alcoholic needs.
At minimum, this is what I sugges for yourself------
1. alanon or similar face to face support group
2. Your own counselor or therapist
3. Financial and legal counsel for any concerns or realities that you think you might need as the future unfolds.
4. If you haven't already done so---get a copy of the most frequently recommended book on this forum---"Co-dependent No More". I think a lot of it wll resound with you.
If alcohol is the main substance your wife is struggling with---you may consider asking that your thread be transferred over to the "Friends and Family of Alcoholics" forum.
I think you may get more traffic and replies on that forum-----about alcoholism.