This happened to me minus the recovering part. I mean mine was clean and sober for 10 years before he met me. He'd also fallen off the wagon and neglected to tell me any of his history until 6 months into the relationship. I completely understand your anger. I was pissed as hell....AT HIM! After the confession, I spent a couple of months wondering how I didn't know, questioning my own judgment and taking responsibility for stuff I didn't own before I got the hell out.
I don't mean to make light of the situation, but we aren't talking about him having a 3rd nipple or something. Being a recovering addict is something that should have been disclosed as soon as it became apparent to your RAB that he wanted to pursue a relationship. Not doing so is lying by omission - not a great way to start a relationship.
JMO