Hi abajak and WELCOME to SR!
I'm very glad you found this place; the people here are wonderfully supportive.
To answer your question: yes, I think you belong here. You seem to feel that your relationship with your AH is based in codependence, and most of us on this board struggle with this.
With regards to the amount your husband drinks, it's more than mine did, and I still felt I needed to leave. I think he generally always had his 4 beers a night, sometimes more on the week-ends. I calculated this and it made my eye pop:
4 x 500 ml of beer = 2 liters of beer a day!
I struggle to drink 2 liters of water a day because it's good for me, and yet he easily drank 2 liters of alcohol.
I also had an uninvolved partner who was more into his videogames, tv shows/DVDs than he was in spending quality time with his son or baby girl. I felt like a single parent with the added burden of an extra stinky loud-mouthed grown baby wreaking havoc around the house. Fun times...
Anyhow, if you have a problem with his drinking, then there's a problem. His manhandling the children is just plain abusive and you have a good reason to be concerned. If you want to know where you stand, can I suggest quietly consulting a lawyer for a consultation? Perhaps jot down all the questions you have about custody and child support and whatnot beforehand so you can make the most of your consultation.
Keep posting!