Hiya, welcome to the forum.
Have you read other posts and the stickies? They hold a lot of valuable info in them that will help you.
From reading your post I would say you seem to be far too involved in his drinking. This is completely normal because at first we think we can control it for them and make them stop by nagging, asking, begging, pleading and threatening...what you're starting to realise now is none of that works. It doesn't work for you and it didn't work for us either.
I came here over 5 years ago with the exact same question "How can I help my boyfriend stop drinking?" and was quickly told "You can't".
Wasn't what I wanted to hear but I stuck around because I was going nuts trying to get him to stop and I didn't like the way I was changing and behaving.
Your BF is a grown man and it's not up to you how much he chooses to drink. That's HIS choice. Your choice at the moment is to stay with a man who drinks. What I'm trying to say is that we are each responsible for our own actions and choices, his choices are his and yours belong to you.
You will drive yourself CRAZY trying to make him stop drinking if HE isn't ready to. The willingness to change has to come from him or it will never be successful.
Have you found yourself counting cans or drinks, measuring how much he has left? Checking up on him? It will only get worse. Alcoholism is progressive.
There will be many more wiser than I answering you, stick around and soak up the knowledge. The only power you have with alcoholism is educating yourself to make the correct choices for you.
The only way you can help him is by detaching, not enabling and looking after yourself.