I 20M together with 21F have been together for 3 years. From the start, I confessed my love to her and she agreed to being together with me. However, throughout the 3 years, I realised and learnt alot of my flaws are affecting her. I have low self-esteem which leads to many insecurities and being pessimistic and an overthinker to everything. My gf points that out and kept getting into arguments and fights with me to tell me where I am wrong and what I have should improved on. For me, I listened to her and tried to change myself, but to no success. Till this day, I'm still annoying her with my pessimistic, stressed mindset towards life. She often asks me, what do I want in your life? But my answer often is I don't really know. We have kept arguing here and there so often which I popped up the qn to her, "If there's so much issue with me then why bother being with me? Why can't you leave me? I tried so hard to change but I'll always be burdening you." She broke down, telling me that it's because she loves me and she's unable to let me go. After thinking it through, I realised that I get what she means. But at the same time, I'm in a dilemma as I know that I kept hurting her and she's often luring out negative remarks about me when she's affected my flaws. I also get affected by her negative remarks, with things such as "Can you stop acting like a kid? You are fucking the worst person I've ever met."
I honestly don't know what to do now. I still care for her and still tries my best to be there for her. But at the same time, I feel emotionally drained. I feel tired to argue but at the same time, I don't want to lose her too. What should I do?