Sounds like your inner voice (instinct) is telling you something. You can't deny the booze hidden in the garage, you admit you don't want to be around him and it's like you are waiting for the left foot to drop – relapse.
Does everyone know he's an alcoholic, do your kids know he's an alcoholic?
You did say fiance right? When is the wedding planned for?
I'm guessing that anger is more hurt and disappointment because you know what you know and you can't UN-know it anymore.