Dear Broken;
I am so sorry this has happened and that you are suffering. These kind of breakups are so traumatic because to us, it seems like they are choosing something so unimportant over us; and it wrecks our confidence. Your boyfriend sounds very much like my Ex. He drank vodka every night, about the same amount as yours. He knew how I felt about addiction issues going into our relationship so he went secret with his drinking. I also hesitated about moving in with him, because things just seemed wrong. I actually never saw him drunk. But other things in his life starting being affected. He had constant headaches, rarely felt rested, became increasingly negative and depressed. I don't know what came first; his emotional issues or his addiction to alcohol, but I guess in the end it did not matter. I am so glad both of us followed our intuition and did not move in. Sometimes, love is not enough.
Welcome to the site; I am sorry for the reason you are here, but glad you found the forum like I did three months ago. It has been a HUGE help for me. It will be for you too. Keep reading and writing. It helps.
Hugs to you