He is dependent physically and psychologically on alcohol and has not been able to go without it for more than three weeks on one occasion five years ago. That says a great deal about him. This is a problem if you are affected by another person's drinking. This sort of problem too thrives on secrecy, time now to bust this wide open and seek support for your own self.
Re your comment:-
"What am i getting out of this relationship- we own a house together, were comfortable moneywise".
I meant emotionally for you, not material things. You are seemingly not getting any of your emotional needs met out of this relationship at all so what are you doing there?. His primary relationship is with alcohol and that is a cruel mistress.
"I worry if we split up how we will cope. I dont know how it works being a single parent and what help id be entitled to etc. If i were a single parent, i dont feel like anything would change for me in the other areas as i do everything else- it would probably be a lot easier without his mess".
Find out by seeking legal advice re separation and property. You do not have to act on it immediately and knowledge too is power. There is advice and help out there, you just need to seek it out for yourself. Also the government based website entitledto.co.uk is also helpful. You seem to be pretty much a single parent now, you're carrying the mental load here.
You've repeated that you do not want your children seeing this as their normal but they are are absorbing this as their normal; this is what they are seeing daily from you and their dad. They certainly do not warrant seeing all this, your reactions both spoken and unspoken to his drinking and seeing the aftermath of their drunkard dad (I'm also talking about the empties in the recycling bin). They will become more aware of all this as they get older too.
I've already mentioned that talking to an alcohol dependent person about their drinking is about as effective as peeing in the ocean i.e. not at all effective.
Please consider attending Al-anon meetings; at the very least you need to read their literature. You are also playing roles in this overall dysfunction too (those of enabler, provoker and codependent partner) and those need to be acknowledged.