my ex is weird what's wrong with him

So a few days ago I was going through my tiktok reposts and I noticed that the cute relationship videos I reposted for my ex boyfriend were still there and I decided to delete them cuz we broke up 5 months ago and what's the point of keeping them if they're about him? Not to mention that we ended up on bad terms and had a big fight. The thing is when I opened tiktok next day, I saw that he had texted me and in the message he was saying "Oww why did you delete the reposts? V (his friend's initial) looks through your reposts time to time and we have so much , What a shamee" . I replied with " Why does it bother you this much? It's none of your business and I can do whatever I want. Weren't you the one who said nothing about me interests you? What's wrong with deleting the reposts that I made about a person whom I have broken up with? ". Today he replied saying " Lol I wasn't actually expecting you to answer, too bad V and I laughed so much" it annoyed me a lot so I replied with sth like "you show how much of an idiot you're again" and another sentence , I don't remember what it was cuz I blocked him right after replying and deleted our chat. I really can't bother arguing with him over sth so stupid and childish again cuz it's NOT the first time something like this has happened. He's always being stingy and backhanded with his words and thinks he's superior and mature just because he's older than me. But in fact he looks so childish and pathetic. He's annoying like he's the one who says he doesn't care about me but why is he acting like this then? Is he seeking attention ? What's he trying to do? I would like to hear what you think about this