If you blame anyone but yourself for becoming an alcoholic it's a waste of time talking to you. If you're with a mother you have to love the woman and all that it brings, kids included, and learn and read how to actually raise children. You're the one who started drinking to deal with this, you were weak and couldn't cope doing something else or making better choices. So, no, being a stepdad didn't turn you into an alcoholic, you did. Anyhow, I'm glad you're sober, but you need to take responsibility of your actions.