Hi Lissajill and welcome.
So other than sparing you any more hurt, he gave no other reasons at all?
Apparently he wasn't very happy with himself if he decided to move out to a recovery center. Maybe that is truly what he needs.
I'm really sorry that you are hurt though. I'm sure it was a shock and nothing that you planned for and that's very hurtful. It doesn't matter at all what other people think you should or shouldn't be feeling, your feelings are your own, of course.
The best I can offer knowing so few details is to look after yourself well, spend time with family and friends, do things you like. What other support do you have besides Al-Anon, are you in therapy at all?
Lots of support here for you too.