You will know when you had enough. It sure does effect the children and confuses them on how they should act with themselves. They see a parent acting like that and feel they can do the same themselves.
From my experience, they have to reach bottom in order for them to see what they are doing to not only themselves but others around them. Right now your H is in the "how it effects himself mode" Nothing else matters. Yes he may be depressed but alcohol on top of that is not helping but making it worse. Yes they have a teenage mentality and after a while hold on to that mentality whether drunk or sobor. They never can hold their own responsibility well.
It took mine going to jail for a while to wake up. Yes, I still have problems with his acting like a child but its hard to adjust their behaviors when they are not drinking. Yes mine has drank for a long time. Part of his problem was remembering when his dad drank and came home drunk slamming doors and yelling. And YES I am sure if he didn't go to jail he still would be sneaking drinks and not stopping. I wouldn't allow the drinks in the house. So he would hide them.
This is when you draw the lines and make boundaries. You should read up on some of that stuff. Its not easy but telling him to leave nicely and that you had enough could be the point he has to live with himself. But then again they usually run to another which never would last because they can't put up with it either.
Getting mad or yelling only makes them worse. They tend to slip up when drinking such as a dui or worse causing fights with others. Then it will effect his job which I see he still goes to but when they get into trouble is when it effects the job.
Make sure its what you want to do and that what you tell him you will go through with. You are handling it much better then I could. I was so frustrated with mine I didn't know who I was at that time. I was also codependent on him for alot of things since I didn't have a car nor a job.
Your H truly needs a wake up call and needs to be there to help raise your son. He needs to help out with some of the work not just play and leave it on you. It will only make you resentful as time goes on. Maybe making him more responsible or telling him this or that needs to be done may help encourage him to be included. Each one is different in their own ways. Since yours hasn't drank for as long as mine it maybe temporary. But sniping it in the bud and trying different things till you exhausted it all may make you feel sure in a decision.
I wish you luck cause its a hard thing to live with. You have what it takes and let alot slide by trying to be a partner rather then a mother to him. Just don't enable him. Enable meaning don't make it easy to get out of the things that are effected by his drinking. Let him get himself out of his own messes.