ExCordis, welcome. I too thought that if he loved me, he'd stop, or at least try to stop. I've learned that it is a disease, and this disease will 'tell' him what to do and put the alcohol first. The seeking of the high will trump everything, even if the A has the best intentions.
I know my AH loves me and our little girl, and yet, before he sought recovery, even that didn't keep him sober. Once after I brought our baby to watch one of his softball games, I thought at least then he'll be coming home after (cuz usually that would be one of his late drinking nights after the game). He ended up walking me to the car, dumping his stuff into the trunk and then leaving to catch up with the team for drinks. Left me standing in the parking garage at 9pm with our 6 month old.
The desire for them is too strong. It's not about whether they love you or not. They feel compelled to drink and are unable to stop it unless they really want to, and even then it's tough.
Yes, we can hope, but hope does not make a life, it makes for a waiting game that may never pan out the way you hoped. Better to take off the rose-coloured glasses and see what's in front of us. When we see reality TODAY, then it helps us find what we need to do. And unfortunately if it's his destiny to wind up homeless under a bridge, then it will happen, and you are no superhero and you cannot prevent that even if you think you can. If he has no desire to recover and you just put obstacles in his way, he will eventually just work around you. And then all you've done is be an obstacle in someone else's life (and a failed one at that) instead of LIVING your life.
You could also think differently about it. Helping does not always mean staying in a relationship, pushing what you think they should do. Maybe helping is stepping away and allowing the person space to find their own way, whatever way it is. Really when I thought I was helping, I was hindering. You share something special (being your first) but that does not mean you have to stay with the guy forever. It just means you have history that you will always cherish. Don't make that to be a life sentence.