Descrtructive behavior with dating?

Does anyone else start feeling like they will never be good enough if you get broken up with? I have had 5 failed relationships and I am 24. I feel super exhausted from it and I have barely even started dating (didn’t have my first bf until 20) After my ex broke up with me 3 months ago, I chopped ky hair off extremely short , self harmed and thought about committing suicide. Yes I know I am not mentally stable I’m on medication and see a therapist. I started talking to this new guy and we are in a relationship but I am so afraid he is going to break up with me that I have this underlying fear of him leaving me. I have very bad anxiety about it and I cry thinking that he will break up with me. I am not sure why no one likes me it really hurts me deeply!