I would think another good indication would be when others decide it for you.
When your family or whomever the recipients of the violence leave you, press charges to put you in jail, etc. I think a lot of alcoholics don't discover their limits by themselves. It's when their families, partners, employers, whoever refuse them completely.
There's another side to your question. It's the question your family is asking, how many times is too many times to keep forgiving? When is the point when you throw them out on the street? (literally or figuratively)