Feel some type of way, not sure why?

It’s been a month since I’ve broken up with my ex boyfriend, a friend told me she saw him on tinder and I won’t lie I did stalk him on social media out of curiosity and seen all the girls he’s now following/liking pics of. I’m not sure why I feel some type of way? I guess I’m my eyes it’s not fair/ I don’t want to see him moved on even though I know I’ll never get back with him, dumb, I know. I guess it’s also because I have no one, not talking to anyone romantically, no friends, not close with family but it seems as though he’s living his life perfectly fine, I’m probably just lonely and sad though (not over him, he’s tried getting back with me and I blocked him everywhere )

Like I know he himself as a person hasn’t changed, he wasn’t even a good boyfriend, trust issues, I gave more than what I got, alcoholic, not ambitious, not independent, etc. I don’t know like I’m not sad over the breakup, maybe mad about him moving on? I don’t plan on getting into a relationship anytime soon but seems as though he’s on that path. I don’t even know why I’m bitter, like I don’t know why I can’t get it through my head that he wasn’t good for me. Maybe him moving on before me and it seeming as though he’s ‘happy’ and living life, idk lol just ranting I guess. (100% sure I’m over him and haven’t been sad over the breakup! Nosy though lol) Anyone else relate?