I am unsure from reading your post whether he is currently actively drinking. I think that as long as he is, the same old will prevail.
I see the sex and the alcoholism as yes, connected, but also separate. He believes he is entitled to his fantasies and that you will always take him back. He seems to have that old guy's club belief that his behavior is acceptable. This type of thinking does not have to be associated with alcoholism, as it is fairly common. *Pukes* from the "mother figure" remark...uggh.
He values sexual fantasy above true intmacy. This much is CLEAR.
I also don't believe he has ever been truly honest with you. You may be more gullable than you think.
Yes, he loves you, as long as you let him do what he wants anyway.
What would happen if you said NEVER again? The ultimatum? What would he choose? This is for thought purpose only, not suggesting such action, that is your choice and could be a very disappointing outcome.
There is a circle of repeat here. Placate you, then back to business as usual.
Where you are at is deciding your boundaries. What is acceptable, what is not. Can you live with it? It's not about him, he's made clear who he is...what do you NEED?
Can you force him to value intimacy above fantasy? No...but you can make him think about it by raising the topic. Sometimes I think some men are simply daft to what a sexual relationship is really about.