Dear HW -
Oh my goodness yes, most of us have been exactly where you are. And I am one of those who includes being abused in my marriage. One of the things I've had to realize is that the alcoholic and/or drug user and/or abuser rarely "gets better". In fact, they almost always get progressively worse. We try, in the beginning, to reason with them, try to make them see what their abusive behavior is doing to them and to us. It is so clear to us. But logic and reason don't work with our abusers (alcohol/drug/violence). Rather, they justify, blame anyone but themselves, further self-medicate to squash any guilt they might have (which isn't much).
With my STBXAH (soon to be ex alcoholic husband), I was looking for a dream man and thought he was it. Trying to distinguish the dream from reality is incredibly difficult, but it can be done.
And as several here have said, once you make the break from the abuse, and start to heal and grow, the end result is an exponentially much better life for yourself, your child, and your future.
HUGS to you HW! Stick around, there is an endless supply of hope and help on this wonderful Forum.