I have issues with my parents and don't know how to resolve them?

my parents were pretty wrapped up in each other when i was growing up, my dad was extremely physically and emotionally abusive towards my mother and had at least 5 affairs during their marriage and then later got hooked on cocaine for 10 years and did some pretty bad things. my dad favours my two brothers and would spoil them and spend time with them and they could never do wrong. when me and my twin sister hit our teens we became obese and he would constantly call us names and threaten us about our weight and eating habits. (i've recently shed the pounds at 20 years old) alot has changed over the last 2 years. my dad is now sober, my parents are together and seem happy and he hasn't hit my mum in the last 2 years. but since 'the big change' i've wanted nothing more than for both my parents to be dead. it seems like the past 20 years have just hit home and i'm pretty much a wreck. me and my mum were close when things were bad, like best friends. now i can't even stand to be in the same room as her and sometimes i can't even look at my dad, i'm so angry at the both of them for what they have done. whenever i've tried to tell them how i feel but they are convinced they have done nothing wrong and just get angry or tell me to shut up. my mum has the attitude like 'you think you've been through alot, i've been through worse' kind of thing and it's like talking to a child, they won't accept that they have done wrong nor will they apologise, it's like nothing ever happened.i have every intention of moving out of our home when i can afford to, but until then how do i cope with being around them? i don't spend any time with my family, i just want to get away from them and never see them again. looking back at how i dealt with the problems at home really upsets me, when i started going out and drinking i'd get into fights, i'd drink till i passed out and slept with ANY guy that wanted me. until last year i was confident loud and social, but now i'm withdrawn and distant and find it hard to talk to anyone even on a basic 'small talk' level, i feel like i have nothing to give and i would rather pretend like i don't exist, i've lost my friends, i've lost interest in everything i used to enjoy and my confidence is at rock bottom. how do i get over what's happened and still have a relationship with my parents? i feel like so much has gone on but i'm the only one who's suffering from the past. everyone around me is happy