What he wants is to continue what he is doing-mooching off of you while drinking and cheating. More important question: WHAT DO YOU WANT?
It doesn't sound like you want to continue as things are, and it doesn't sound like he has any real intention of quitting. Finding the answer is easy, it's the execution of what is next that is the hard part. I left it September, with my 2 young daughters in tow. It is not perfect, but it IS better.
And yes, go to Alanon. I stopped making excuses and went to my first meeting this week. I highly recommend it!
M