Can’t move on

I (29/F) dated a my ex (27/M) who broke up with me in the worst possible way few months ago after promising me a future and then finally using everything about me as the reason to break up with me when an arranged marriage proposal his parents found for him came up. He made me feel bad about who I was as a person and turned everything he said he loved about me as the very same things he hated at the end. I can’t move on because it came out of the blue for me and I genuinely loved him (and I felt loved by him as well) but he seems to be functioning well. I have to see him in office from time to time and he seems to be doing well while I’m the one struggling. I really want to move on but can’t. And the worst part is I keep blaming myself when I know deep down there wasn’t anything I could have done. I know I didnt deserve to be treated that way and I know I should try be wasting my tears on someone who hasnt even reached out once after ending things over six months ago. Any similar experiences and was wondering how best to process this and move on?