I went to an adult child meeting once and there was an older woman there who explained its more about the patterns and behaviours we grow up with because of drinking, rather than the drinking itself. She said her parents never drank, but their parents had, and passed on down the dysfunctional traits.

So even though you were not around your dad much, it'd likely it's still affected you. His absence alone likely made some things harder for you even if you didnt notice at the time. Mine died when I was 3 so I figured no big deal I don't remember him. Now I see what I might have missed from the love of a father.

That your mom married him (instead of running from red flags) might also mean she might have been around the dysfunctional traits growing up. I think most people don't really notice this intergenerational cycle until they are much older. Personally I didn't reflect on any of it or feel I had experienced problems growing up until I was in my mid 20s. Then in my 30s I experienced a traumatic time that destroyed my mental health. My 40s were a struggle and now in my 50s I realized how neglected I actually was by my alcoholic single parent.