How to get over unrequited "love"?

I recently fell for someone I met through friends. From my perspective, he's an amazing guy and has all the qualities I'd want in a partner, basically everything going for him (cute, fun, smart, kind, etc), a total catch. We ended up going on a few dates, until he decided he wasn't feeling the romantic connection he needed with me and ended things.

I am doing my best to move forward, but honestly, I'm pretty crushed. I know what it's like to be on the other side and not feel what you want or need from someone, but honestly thought things were going well with us, and that we made sense. I got my hopes up. I'm trying not to put him on a pedestal, but I'm pretty bummed that someone I saw as a good match for me, and felt hopeful about, evaluated me and said no. I know my ego is bruised, but it also is making me feel like, okay, if a guy as great as him doesn't want me, I must be lacking and not good enough somehow. Like he was out of my league and maybe I need to look for less. I can't stop feeling sad that I missed the opportunity to be with him, that I wasn't enough for him. I keep hoping for another chance, to be an even better version of myself, and feel like, maybe if I had just been a little better, played it a little cooler, he would have eventually fallen for me too?

How do I swallow this pill and get over it? I so rarely meet people that I like (I'm mid 30s) I'm having a hard time letting this go.