My parents divorce when my sister (21f) and I (19m) were very young. Our dad cheated on mom and immediately tried to alienate us from her by saying the woman he cheated with was our new mom. She was pregnant too which only made everything more fucked. The other woman lost the baby at like 5 months and she ended up leaving dad because of it and because of us and our mom. Dad blamed mom for all of that. He used to say mom cursed the pregnancy and did some kind of magic to make her lose the baby. It was an insane thing to hear as a really young kid.
He eventually got married again to someone else and my sister and I were still really young so he tried to turn her into our mom. He would punish us for using her first name and she would punish us for it too. They used to tell everyone she was our mom. They told our teachers, our friends parents and literally anyone they interacted with that she was our mom. We got into huge trouble for saying otherwise.
My dad would tell us mom was trying to stop us from being a family. He said mom made his wife sterile and accused her of all kinds of fucked up things. His wife went along with it and would go crazy at mom in front of us and then try to make us side with her. Because we didn't turn against mom and didn't believe them they got more crazy with the accusations and attempts to ruin our relationship with mom.
My mom fought them in court, she had us in therapy, we spoke to people from CPS and the courts and CPS let this go on for years. I was 14 and my sister was 16 before they reduced dad's contact with us to supervised visits once a month. And even still we needed to talk to him twice a month on the phone too. We hated it. We hated them. We saw how awful our dad was and mom never had to say a thing against him for us to see it.
Me and my sister went no contact with dad once we turned 18. She hasn't spoken to him in 3 years while it's 16 months for me. I might have fucked up though because he kept reaching out via fake accounts on socials and then he used a family member's phone to call me and I answered because I didn't realize it was him and I let him talk and then I told him he was a shitty person and father and explained that all the stuff he did to mom and us made him that way. I told him he was the one who cheated yet he tried to alienate us from mom and tried to get us to replace her with some rando and he told us over and over that mom was the reason the baby died that time. I told him all that stuff made him a person I didn't ever want in my life and I told him there's nothing to fix it. I ended the call and texted that relative that I wouldn't answer their calls again or texts that were clearly from dad.
I have family members on dad's side asking me why I had to be so awful to him and why my sister and I aren't grown enough to approach an adult relationship with him maturely and to see the good in him. They even said he fought so hard for us and we should appreciate him being there.
AITAH?