mentally abusive exes

hey guys! I’ve been in some pretty mentally abusive relationships since I was about 14. they’ve really just stuck with me and created a lot of issues. I now have the most perfect boy ever. he treats me great and loves me unconditionally. I just have a hard time letting him love me. I feel like i’m not good enough and that he’s gonna leave me and break me like everyone else. I just don’t know how to fix it. if anyone knows how to help please let me know