"I would never let someone treat me this way" is an appauling thing to say to an abuse survivor. You have no idea how you would respond if you were them and in that situation. Everyone imagines that they would leave, yet if it were that simple, domestic violence would not be the endemic it is today. The implication of that statement is that it's the victims own fault for not leaving, and that's called abuse apologism. It's a disgraceful, victim-blaming attitude that simply should not exist, especially not in a forum about abuse. Maturity has nothing to do with it, and suggesting it does is revolting. Really your whole post ^^ was awful. You should delete it and apologize. There is absolutely NO justification for abuse EVER. Maturity is irrelevant, and calling someone immature for how they respond to abuse is disgusting.

Friend, your story sounds a lot like mine. I met my (now ex) partner when i was 15, we started dating when i was 16. We had our first child when i'd just turned 18 and our second when I was 20. We separated when I was 23.
I thought he was the love of my life, that i would never have such passion and caring that I did with him. The truth is, he made me feel like garbage, by calling me fat, a ***** etc. so that I would feel like no one else would have me. Like you, I often found myself apologizing to him after he abused me. Like you, i was baffled by his seemingly irrational rages; one that stands out is when he beat me with his fists and threw me across the furniture while i was 8 months pregnant because i didn't return his library books. He never told me he'd even borrowed them.
In the end, he nearly killed me. In a rage, with our daughters sleeping in the next room, he grabbed a hammer and chased me around the house. I tried to escape but he'd locked the door and hidden the keys. I curled up on the ground trying to protect myself as the hammer came down. By some miracle, i was able to grab and scramble to my feet, wrestling it out of his hands. By all rights I should be dead.

Abusers can change, they can change because everything they do is a choice. Even the stuff they claim is a 'loss of control'; it's all calculated, it's all deliberate. They can change, but they don't. They enjoy abusing, it works for them. They get to let out all their aggression and rage (many are sociopaths or psychopaths by the way) and in return have someone who will do everything they can to make them happy and take all the blame.

No one can tell you what you should or shouldn't do, you're the expert on your life and your situation. I would strongly recommend reading the book 'Why Does He Do That' by Lundy Bancroft. I have a free PDF download link if you're interested. I'd also recommend looking up something called 'MOSAIC threat assessment', which is a free questionnaire that gives you a numerical result telling you how potentially dangerous your partner is. Both of these things will help you understand your situation better and help you plan accordingly. There are also lots of practical things you can do to increase your safety, whether you decide to stay or leave. I'm not sure if i'm meant to post links here, but PM me if you want me to send you the links.