Hey Justin.
Oh my, I really relate to this. Different conditions regarding details, but the story and the feelings you are describing are very similar to something I experienced in the past. I had a bf for several years, right in the beginning when I started to drink heavily, and my drinking escalated in parallel with the progression of the relationship. He was an alcoholic, too. I never had a romantic relationship with another addict before/after. With time, we developed something that I ever since call a serious addiction to each-other, mutually. It was just as detrimental as my drinking, but similarly appealing and irresistible as well. I still don't know which one was easier or harder to kick for me in the end, I handled the two issues at different times, a few years apart. I wrote about this story here on SR excessively, but I think you were not around back then, so here is a brief summary.
The relationship was before I moved to where I am now and we were living together for a couple years after a very stormy beginning, although also spent a lot of time apart since he travels all the time and I do also often (did even more often back then). But my alcoholism and this relationship was totally interconnected: as I said they developed together in the first place and then one triggered the other very efficiently. I ended the relationship after a few years, and I also made huge changes in my life: moved to a different state, new job, even new professional field. But did not stop drinking back then, so in that sense you are in a better position. I stopped all communication with him at first for a few months, but then fell back into it slowly... only emails for a while.
Then we met again IRL at a conference -- it wasn't planned to get together again but we both knew we were going to attend the conference. Long story short, we first just talked at the conference site... then decided to go out to dinner to just chat and catch up. Guess what: a flood of old memories... but we parted after the dinner even though I did go up to his hotel room for a few minutes, but we had enough self-control to separate then.
Until I got back to my own room an hour later... then we start emailing again and... plotting the "relapse" for the night after. And that was what happened: I went back to his room at the end of the next day, he was waiting for me with a bottle of rum... and you can imagine the rest.
As I said I never quit drinking up to that point, but after that, I got into it worse than ever for a while. And into the relationship as well, even though it was no longer possible for us to be together physically anytime since we were living quite far from each-other (thank God, at least that!). It was a very serious setback for me in everything with my new life, although it did not start immediately. But eventually we got back into the obsessive communication via email, while drinking separately... it got really bad.
It was a Herculean effort for me to end it again, wasn't linear, and I started being very irresponsible in my daily life again. Drinking getting worse and worse, I developed conflicts with people in ways I never did/do... not pretty. Managed to cut it completely in the end, but the drinking took a couple more years to tackle.
It wasn't the true end of it though. Even though the relationship between the guy and myself truly ended, I started "looking for him" everywhere and seemed to "find it" in other people... lots of *** mental projections, and lots of troubles due to them. I'm still dealing with some forms of all this although now it's quite different, but still hard to deal with it and I can't seem to succeed completely on my own because it's a gigantic and very old projection complex... so I'm getting help with this now. I totally should have done this like 20 years ago or earlier. It can't stop to amaze me just how far and deep this rabbit hole goes. Please don't procrastinate therapy
I don't want to give you direct suggestions, just wanted to share my story. I hope you make the right decision for you about it. I know how darn hard it is, believe me
Btw, I also had that "free" feeling for a while before that relapse (with him). And even after it for a few days, like "oh I can do this now no problem". Ha!