i need advice!

so.. to be clear, i struggle severely with personality disorder. my partner read my journal. and he read something directed towards him, saying he was perfect but that i wasn’t sure he was the one for me. i pointed out some of his biggest flaws, and claimed i had spent most of our relationship angry / anxious/ unhappy. this is very common for me in friendships and relationships to feel unpleasant feelings and it’s something im working on and trying to navigate myself - which i stated in said journal entry he read. but he is heartbroken, and im heartbroken to be the one causing him this pain. i know he needs time and assurance but i feel so helpless, what can i do?