Damn that's hard, sorry you had to experience that. My mother was a teen who couldn't fend for herself when she got me and my father was a drunkard, never hitting anyone but always shouting physical threats around. In the last years I've grown the suspicion that he had the same issues as i have, with no therapy. (He died stumbling while drunk hitting his head alone in his messy apartment, so i can't ask him and i wouldn't if he lived anyways)
AvPD is developed in the first few years of life (there is definitely a genetic component in play, but there is not much research on it, since we are not problematic for our surroundings and tend to not seek help because we don't want to inconvenience anyone - any researcher will have a pretty hard time finding enough of us), so i can only make an educated guess what happened back then, which probably was the same stuff i experienced later.
I think i might have had a chance at a much better life if the first few years had been stable, just so that the core of my personality had enough time to form. I am missing the basic trust most people have that everything will turn out all right and that what people tell me in regard to my relationship with them is the truth. Like, people can tell me straight up they enjoy spending time with me and i don't believe them.
I hope you have at least a bit of that basic trust going for you. If you have, hold onto it, it's something precious.