What do you stiull get from this relationship now, what needs of yours are being met here?. Something innate within you is still keeping you within this and this is why I asked you originally to read up on being co-dependent. This unhealthy state often features in relationships where alcoholism is a feature.
It is NOT your fault he is an alcoholic. Thinking otherwise is your co-dependency talking.
Re this comment:-
"(I think) it would be so much easier to leave if he was a 'rolling home drunk every day drunk' but he isn't. He's a binge drinker and it can go weeks/months in between and even worse he's not that different from our friends. (Friends wonder what I'm on about). He doesn't come home and beat me up and he doesn't ever get to the things listed in the 'soberblogs'. But no one else but me is let down by him not coming home when he says or never wanting to leave the party. Or mopping him up after a fall or getting him away from assholes he tries to befriend because he's too drunk to recognise they are assholes. Or falling asleep at functions we've paid money to attend. Leaving our house when we have guests to go to the pub because I put Erasure on to dance to. Shouting at a waiter 'Oil Fucker' to discuss a bill. I feel like I'm going mad".
Not surprised you'd feel like you're going mad. Anyone would feel bonkers in such circumstances. He is the root cause of you feeling mad, sad and confused.
Many alcoholics actually only associate with other problem drinkers, those people are the only ones socially who put up with them.
Ok, so he does not beat you up. That does not make the other crap that he does any less bad does it?. You're being dragged down with him by associating with him at all, you're likely to be pitied by them as well.
He makes me cringe inwardly and you have enabled and put up with him for far too long. Why did you try and get him away from arsehats or mop him up after a fall?. Those behaviours enabled him and certainly did not help either of you. What you have tried to date simply put has not worked and will not work either. All that enabling does ultimately is give you a false sense of control, that is what doing all that for him gave you at the time. It is a relief short lived.
How many people in your own social circle know he is a drunkard?. Not many I daresay but alcoholism as well thrives on secrecy.
Are you really going to disengage properly or continue your ride on the merry go around hat is alcoholism?.