Simple answer? Quit drinking.

Long Answer: No one can answer any of this but you. You need to get professional help for your drinking problem before you even attempt to tackle the stepfather issues.

Solving one without solving the other will only cause you more trouble. You need to get the drinking issue cleared up BEFORE you deal with the kid issue. Without doing it that way, any progress you make will just be overshadowed by the alcohol.

Good luck.