Seeking Forgiveness After a Difficult Situation

Salam everyone, I hope you're all having a blessed Ramadan. I just need some advice and please be kind in your responses. My father has been abusive towards my mother, me, and my sisters for as long as I can remember. I'm now married with a child and don't live at home anymore, but I've always tried to stand up for my family when I'm around. I'm not the type to stay quiet-I speak my mind, and if I'm disrespected, I can get disrespectful back. For about a year now, my father has been really miserable, especially towards my mom who's recovering from cancer. My sisters work so hard, and honestly, my father is blessed to have such a caring wife and children. But all he does is speak badly about them and take out his frustrations on everyone. He doesn't say much to me since I'm married, but seeing him treat my mom so poorly is something I can't handle. He starts arguments over nothing. I've been staying at my mom's house for a few days to visit, but his behavior has made everything tense. Last night during sahoor, he was getting angry at my mom and sisters over something small-like the cat knocking over an empty cup. I got upset and said something harsh about the cat out of anger, and then my father started making dua against the cat. I added more angry words, and things escalated. He wouldn't stop, so I told him to be quiet. My mom stepped in because she saw he was about to hit me, but I didn't back down because I was tired of the verbal abuse. He ended up slapping me hard, and in anger and self-defense, I slapped him back. He was shocked and then charged at me, grabbing my hair and hitting me more. My sisters had to step in to protect me. My husband wasn't home at the time. Afterwards, I was so angry I couldn't stop saying things to hurt him. I called my husband to come get me. My father started packing, and we were worried he might take important documents, so my sister took them from him. He almost hit her, so I stepped in and started yelling again-he slapped me multiple times, injuring my ear. My ear has been ringing and I feel weak from it. I ended up calling the police, and as soon as they arrived, my father acted completely calm and normal. SubhanAllah, it shows he could control his anger all along. Alhamdulillah, my baby son was asleep and didn't witness any of this. My husband told my father he can't come near me or our son until he apologizes and changes. But I also feel like I need to ask my father for forgiveness, even though I don't want to because it might excuse his behavior, especially after he hurt my ear. I've forgiven him so many times throughout my life for his abuse and humiliation. For example, I forgave him in my heart the day after my wedding, even though he never apologized-he ruined my wedding day by cursing and insulting me all morning because I set a small mahr for my husband, who was struggling financially at the time. He also had no right to hit me since I'm married now. I'm an adult, and I've seen his abuse my whole life. Yes, he provided for us, but he always made sure we knew it, and it was the bare minimum. Since this happened, I can't stop thinking about it. I feel like my Ramadan isn't accepted at all. I sinned by hitting my father back and cursing at him, and I feel like I've ruined my month of worship. I've been praying my salah late, and it's taking a lot of effort just to get up for prayer. I'm in a 'give up' mindset. My question is: how serious is my sin, and what should I do to seek Allah's forgiveness? Do I need to ask my father for forgiveness in order for Allah to forgive me? I don't want to apologize because it might enable him, but I'm scared of Allah's punishment. I also worry, Allah forbid, that even if I'm a good parent, my child might someday treat me this way. Please advise.