I surely do understand and oftentimes have shared the anger and frustration and thoughts of "how can you do this to me... Or our baby?".
One thing that has helped me, after getting the three C's down, was the realization that everything that happens when it comes to the disease she is fighting I am neither ignorant nor powerless. I've chosen to be here and it took me a long time to decide to get on this ride but once I did so I did so knowing the worst.
She might and probably would relapse - two small ones this year
She might not always be the joy she can be while struggling through year one of recovery
There may come a day when the alcohol wins and either she leaves because I won't live with an active alcoholic again and she chooses going to somewhere or someone else instead of rehab
Choosing to commit myself 100% means I will probably never go to another Jimmy Buffet concert (lol), I will learn to enjoy great food without wine, I won't go out to parties or events where alcohol is all over.... My life will be different due to her disease.
She may never realize what I (and many here feel) about the time before she got sober and the relapses since or yet to come.
BUT I became OK with all of that when I realized that I made a decision to be in this situation and have chosen to remain in this situation despite the bumps in the road and have decided that I choose to continue knowing the risks and the high probability that we are not through the woods yet and may never be.
I have a choice. We all do. This isn't to say "well if you don't like it, it's your own fault". It's just to say that we are not powerless and not victims of this disease. We choose to deal with it in our lives or we choose not to. We are not 'stuck' once we realize that and it makes it much easier to deal with when we accept that.
Hope that makes sense. For a time I was very much afraid that the rest of my life would be like it was when my wife was drinking - fear of what would happen next and where the next crisis would hit from. ...but when I decided I was going to commit to my wife I didn't commit to dealing with living with an active alcoholic, my decision was based in the clearly communicated condition that my commitment to her depends on her commitment to sobriety. She has my unconditional love but knows that I will never live that way again.
So to the OP - you made a hard choice and a painful one but you made the choice that you did not want that life and you walked away to save yourself. Be proud of that. You devoted a lot to this person and it sucks to feel that everything you did was 'for nothing' but maybe it wasn't. Maybe walking away was what it took to save him AND yourself.
Hang in there. Tomorrow is a new day and YOU get to determine how it goes.