i am in a dilemma (toxic relationship)

I'm in a dilemma. I don't know how to convey it properly, but my feelings are mixed at the moment. I am in a relationship that can be said to be a little toxic. We both have mental health problems, but it was me who always understands him. Startinglast month he disrespected me, worse than before. But because I love him, I can't treat him the way he treats me, even though sometimes I get upset. From the start we dated, his behavior always made me feel guilty, even though he was the one who was wrong. Until this time I feel guilty for his mistake. Often times I feel like he dumped me, he asked me to stay away and said that he was bored, but when I walked away from him he just got angry, annoyed, and blame me. I am stressed enough until it impacted my body, also i lack of enthusiasm. One day I was excited to go to college but he came to make trouble, so my enthusiasm for college was lost. This relationship had a devastating effect on my mental and physical health, and disrupted my studies.

My dilemma is, I still love him. I know if I leave him, he won't be okay. He needs someone to stand by him, he needs my love, he needs a reminder in his life, who else could stand there for him but me. He was the type of person who was rude in acting and speaking, not without reason he was like that. There is a history of his childhood, he comes from a broken home, he also lives in an area where most of the people there is like that, rough. I want to help him, maybe not as perfect as I want, but at least can lead to better things for him so that no one will be hurt in the future if I am not meant to be with him forever. I want the best for him, as well as myself. I am in a dilemma, what should I do?. I didn't want to leave him, but I also didn't want to endure the inner pain that I endured for more than a year, I didn't want to feel this mental and physical pain all the time. i need help, i need advice. thank you