Hello and welcome to the forum. You will find many wonderful people here who understand exactly what you are feeling and going through. I remember very well the gut wrenching pain in my stomach I felt the first time I left my husband at Rehab. My heart goes out to you because it can be overwhelming, scary and feeling like everything is coming apart.
The fact that your wife has asked for help is WONDERFUL. She may very well be a different person.....different in that she is seeking recovery rather than being an active alcoholic. The journey of recovery is all about change. Alcoholism is a horrible and progressive disease. The sooner recovery is sought the better for anyone suffering from the disease.
Check out all the stickys at the top of the forum. You will find a great deal of very helfpul information about the disease.
Most important.....what are you doing to take care of yourself? Are you involved in Al Anon? That is a great place to start if you are not already attending meetings. You might consider seeing a counselor to help you work through your feelings as well. Come back often and keep posting.
Remember the three C's of alcoholism:
You didn't cause it
You can't control it
You can't cure it
What you can do is take care of you. All the best.