I (M17) live in a toxic household and I contribute to that but I wanna know if I’m TA for this particular part of it.

So my parents were married and seemed happy when everything fell apart. My mom found out she had a brain tumor and on that same day she found out my dad was sleeping with her best friend.

I was 10 at the time and for like 5 weeks life was crazy with my dad and “Hayley” who was meant to be my mom’s best friend trying to make her forgive them. My mom started having seizures because of the tumor and I think because of the stress too and she died five weeks and two days after she was diagnosed with her brain tumor.

My dad and Hayley moved in together after my mom died and they decided they would try to raise me and my sister together. My sister was 8 at the time and my dad has said she took her cues from me but we did not accept dad and Hayley and we acted up a lot.

I yelled at them, called them names, refused to listen when they asked me to do something and I told other people what they’d done. All of dad’s friends, all of Hayley’s friends and our neighbors knew and mostly because of me.

I interrupted their wedding a bunch. My sister did but not as much. We wanted to live somewhere else and they refused. They got us all into therapy and I didn’t put any work in to fixing things. My dad and Hayley had two kids and I refused to help or care.

I make a point of telling or showing what they are and what I think of them. For my dad that meant cutting him out of photos and I say every now and again that I’ll change my last name to mom’s (she never changed hers when they married). And I talk about my maternal grandpa being the man I want to most be most like because he’s the best guy I know. But with Hayley? I remind her every time that she was supposed to be mom’s best friend and she was a backstabber who cheated with my dad instead. And I do this in front of other people if she tries to act like my parent or take praise for my good behavior around other people. She told me I need to stop bringing it up several times but I ignore her. I tell her I won’t ever stop.

Her aunt died last week and she told me I needed to help out around the house more while she was with her mom and her cousins. I refused and she told me this is what the oldest sibling and oldest child does and I reminded her I wasn’t hers and brought up the affair again. She broke down and I told her I didn’t feel sorry for her and she told me she felt guilty enough and like mom haunted her enough and she said I was doing nothing but driving her crazy and making her feel like she had to isolate from everyone because otherwise the whole world would know with the way I act. She told me I was bullying her and that I should go after dad and not her. I told her I’ll go after both until I can cut them out of my life for good. Then I told her she didn’t deserve to have a happy life after what she did.

My aunt (dad’s sister) came over after Hayley called her and she asked me to stop bringing it up. She told me Hayley and my dad don’t need to be forgiven but that reminding Hayley like this and shaming her and making it difficult for her to have relationships where people won’t know and judge isn’t okay because the kids she and dad have together will suffer.

AITA?