How to tell my abusive parents I’m moving out

So I’m, (23f), prepared and ready to move out to live with my boyfriend, who has already moved into our new apartment. It’s all been done without their knowledge, and they have no idea I have a boyfriend. Trust me when I say they’d never be accepting of him or my relationship with him.

Anyway, the problem is that, like others in this subreddit, my parents are strict and overbearing. I’ll try to keep it brief, but while my mum is generally unsupportive, it’s my dad that I’m worried about. He has a history of acting aggressively in response to my actions, one of the worst being when I told him my intentions to move out for university. He wasn’t directly violent, but he got drunk and threw a piece of furniture, during my birthday dinner with my older sister no less 😓.

I got my way in the end, and he walked away thinking he was a good dad, and there’s been no issues since, but only because I don’t tell them anything. They have no idea what kind of person I am, the things I’ve done, that I’m capable of. They see me as this naive, vulnerable girl and because of that, I don’t think they’ll be okay with my intentions to move out. I don’t know if there’s any reasoning with them, they’re just so stubborn.

I don’t intend to tell them about my boyfriend. It’ll be a “female friend” instead, and I’ve been thinking hard about the best way to deliver this news, even though I don’t think it’ll matter much in their eyes. My mum will try to dismiss me — she already has, when I first brought up the topic, and she hasn’t mentioned it since — and my dad…I don’t know, I hope for the best and expect the worst. I do have a good support system, and I am prepared for a scenario where I could be kicked out or I feel unsafe, if it gets to that point.

I’ve already seen great advice on this subreddit for similar situations, such as making sure I have all vital documents and my money in a safe place. But the real problem that I need help with is this: I have three younger siblings that also live in this house, and I dread the consequences that my actions will have on them. If I leave quietly and leave a note, I’m worried he’ll lash out at them, and if I argue with him, that’ll be scary for them to witness. Either way, I feel like my act of moving out will make him stricter with my siblings, especially my sisters. Again, I don’t think he’ll be directly violent, but he is aggressive, and I know my mum won’t be as defensive and she should be.

It’s easy to say that I need to prioritise myself, and if that’s what it comes down to, I guess I will. Even so, is there any way around this? I really can’t stand living in this household any longer, but now I’m feeling so anxious and paralysed. Any reassurance or advice would be greatly appreciated, thank you.