OP, I understand. I have been through something similar, though not as bad as your situation.
He won't change. I promise you that is the truth. He won't see the need for him to change, or he just cannot. Either way, the only control you have over the situation is over your own actions. It is easy to become paralysed with indecision because of fear of the unknown, of the sunk costs fallacy, cognitive dissonance and from trauma bonding. Google those last three phrases.
Also don't slip into codepedency where you think its your job to fix him. It isn’t. And you can't. There is zero chance that you can make him understand your feelings, or change his behaviour.
He is violent. Repeat those words out loud every day. He is violent. When he forces his dick into you, when he drags you and pins you down, when he punches walls, when he throws things, when he menaces you and your DD, when he intimidates and tantrums and controls and punishes.
You can turn yourself inside out trying to understand him. I did too. I learned he was probably a narcissist, a sociopath or had a personality disorder. But really, none of that matters because you can't change it. He is who he is, and that involves being nasty, violent and abusive. And he doesn't care about you or your DC. Not really. He will say he does but he only loves himself.
Sorry, but it is a reality that you and your DC are being abused. You are not taking steps to prevent harm to them. You've got some knowledge of safeguarding, so you know the implications of this.
It doesn't matter that sometimes he is nice and buys them an ice cream, if sometimes he also punches walls and verbally abuses their mother in front of them.
I understand that it takes a lot of strength to make this stop, because leaving him is the only way you will make it stop. Nothing you say or do while remaining in a relationship with him will make it stop.
Your DC can have supervised access with him afterwards, if that is appropriate. They can still have a relationship with their father, but living with him is bad and harmful for them. You must accept this. Your DD is trauma bonded. Separating for her just means both parents live apart. But she will be safe and so will you be.
In the end, I got the strength to leave him for my DC, not for myself. My self worth was ground down so much I couldn't do it for myself. Please find it in yourself to do it for your DC.
And you don't have to do it alone. Women's Aid, Rape Crisis etc will help you.
Please also do the Freedom Programme online. It is very cheap and easy to do and will be an eye opener for you. It was for me.
I cannot tell you how amazing and free I felt the first night on my own. My space, my bed, my house was my own. I did not have to suffer any more tension, arguments, fear or abuse. I felt free, happy and utterly relieved. My DC thanked me for leaving him. Hold the idea of that feeling in your mind and please take steps to make it happen.