Would you be okay if your partner stayed friends with their ex?

I tend to overthink shit and then do some stupid shit after. I dont want to do it again. I just need someone to tell me this is nothing to be worried about.

A week ago my boyfriend followed his ex on instagram, then days after his ex added him on facebook. As the petty, pathetic pc of shit that I am, I got hurt by this and he probably noticed something was bothering me so he asked if im okay. I told him everything, (by everything- I said I got obsessive and got worried that "what if they're private messaging each other? what if his ex wants him back and he chooses her?" and other shit). He explained, he said it means nothing and that he loves me. He said there's no reason to doubt our relationship. I felt better and basically tried to forget it and I did.

I told him I didn't want to tell him what he can and cannot do. So nothing changed, they're still reconnected on social media. I let it go. Just minutes ago I saw him posting on some group page. Its basically a page for fun and the intent was mostly for single people to meet and flirt. My cousin (who's friends with my bf) is also in a relationship and was also included in this group page, so I chose to ignore that my boyfriend was in it too.

Basically my boyfriend posted something on the group and on the comments section I saw his ex's name in it. Its safe to say im overthinking everything again. Why can't he stay away from her? willingly. I dont want to tell him "block ur ex" and shit because I want him to make that decision himself. He obviously doesn't want to. I don't know im doing this "creating problems that aren't really there" shit again.

Somebody just tell me im being pathetic and petty and that there's nothing to be worried about. (they go to the same school lol and we dont).

This was very hard for me but I told my boyfriend how insecure I am about our relationship, I thought it would mean he'd think about how I feel on petty shit. I know being insecure is MY problem though dont worry.
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can someone like maybe give advice on what I wrote below the question pls
Would you be okay if your partner stayed friends with their ex?
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