I went to inpatient for a month this summer. I befriended a woman there who was there for different reasons than addiction and her husband served her divorce papers while she was there. It was difficult on her, and in all honesty I don't know how much of the whole situation I really knew, but I was glad she had the support of the staff and other patients. At least she was in a safe place to absorb it. There were children involved and they had been married for over 15 years though so very different.
I would highly suggest talking to her therapist at the rehab. My experience was that I had a primary therapist who ran the small group I was in 5 days a week.
I guess the question is how much did your wife actually realize she was hiding? I am not at all minimizing the impact it has had on you, but denial is a pretty powerful thing, and sometimes the ugliness of the truth isn't even apparent to us. I can tell you that early sobriety is a boatload of work and pretty intense. I have been married almost 18 years, and I don't know if I would have the wherewithal to sustain a new relationship and stay sober. I don't mean to confuse the issue, but being on her own is not necessarily the worst thing in the near future. Either way, you aren't going to get her blessing on this, so you have to be sure that you are making this decision about what you feel is right and right for you.