Struggling need help

Today we hit 3 months after officially breaking up. He was the one who ended things brutally and unexpectedly, and was so harsh on me. My reaction to the emotional abuse was blocking him immediately on all social platforms. I’m struggling to move on though, I still wait for him to come back, I still look at his social media from other accounts. He has a business account that I unfollowed but I keep looking at the chat status if he gets online or something because it comforts me that he might contact me through it, or just the idea that he might be stalking my social media i guess. I know this is bad, and it’s not helping, i genuinely want to move on, it was a toxic relationship with a narcissist. It will take me days to write down all the harmful things he said to me, and the fact that he was never an apologetic person. I know I shouldn’t care, but why do I care??? It hurts me so much that I care, And why am I waiting for someone who hurt me deeply and had me walk on eggshells for 2.5 years? Only to leave me after all the promises. This is so painful, I need help and advice. How can I get him out of my mind😭😭😭😭