From a child of a marriage

Right now, at this very moment, I’m stuck in a situation which I so vehemently despise.

Just for background information, I'm a 17 year old girl from a Muslim family living in the middle east, nonetheless my views are rather "western" and not so conservative.

P.S apologies for maybe posting in the wrong group?

To start, my parents have been married for a good deal of time, around 20 years and they still "love" each other though I'd question it now. However, there comes a "new" woman who is not so new and someone my dad knew way before my mother. So yes, I could say he cheated and I agree. To be direct, my wants to marry this new woman (as polygamy is allowed in the Islamic Law)...

Everyone disagrees. My family disagrees, "her" family disagrees and so does my father's. My mother is so deeply hurt and has been concealing it for years up until now. I've failed as a daughter, and I wish I could redo the past few years. To be a better person, and a better child. It wasn't until I had a chat with my father that I realised there's no turning back. The marriage would have to be signed off and my family would never be the same.

There's no way of convincing, as my father is completely dismissive to how we feel, claiming he's exercising his "right" as a man despite our réactions (this sounds diluted, our réactions were way worse but I would prefer not to elaborate). Although, if everyone's reaction is this bad then shouldn't that mean something? No, he completely does not understand how this decision is affecting my mother. And because it does, it's affecting us.

In addition, the way he spoke illustrates how he truly is. Selfish, egocentric and inconsiderate of other people as long as it's "acceptable" by hard set rules (the law). I would have never expected such disgusting behavior from him, or maybe I should have. It all adds up.

If this goes through, I won't even be able to bear being in the same house. Though this may seem contradictory, but I'd like to move out and live on my own. The issue is that I don't want to leave my mother, I practically do not want to ever interact with my father unless it's absolutely necessary. I'll definitely visit my mother and allow her to visit me, that is if my decision is allowed.

Yet, I just want an alternative.

You may agree with my father, and that's fine. But I don't and such actions to me are so immoral I don't want to associate myself anymore.

Sorry if I sound kinda incoherent lol