Hi Justwantadonut, I like your username as well! Glad you decided to post.
Sadly, I don't think this is all that unusual. You two get in to a relationship, all is well, he drinks, you don't care - what could go wrong??
What could go wrong is alcoholic thinking.
It's one of two things here (in my opinion). After a period of a year, despite what you told him (don't care if he drinks, drink, don't drink) he decided, perhaps, that he should quit, get back on the straight and narrow and live up to this relationship.
No need to say how that went.
Or he is in to something new, some new drug or just went off the deep end with alcohol (doesn't really matter, result is the same).
There is a lot of shame, generally, in being an alcoholic. Regardless of what you say, they are making their own plans in their own heads (as people do).
You may not have demanded he quit but your mere presence may be a demand to him.
Hope that makes sense. I'm so glad you have his things on the front step and hope you got all your stuff back in time to go to work.
I also hope you will keep posting.