Physical abuse would be a dealbreaker for me. Please contact a Domestic Abuse hotline if you are the one being beaten. Abuse is a separate issue, apart from alcoholism/drug abuse. Many addicts are not violent. Please seek help right now.
I think the disease thing is not so much an excuse as it is a real problem which has to be dealt with - it isn't just a character flaw, there are physiological changes that take effect with repeated substance abuse. This is not what causes domestic abuse, though it can exacerbate a predisposition to violence.