Why did my ex unfriend me on social media?

I thought we ended in good terms. The situation was weird though. We’ve been on and off for a while and he was just going through a lot and he broke things off with me but like I said, it ended in good terms.
We were obviously upset about it and he didn’t unfriend me from social media right away but when I posted pics of me and my friends having a good time, that’s when he unfriended me.
It hurts me because it makes me feel so unimportant. Especially since the breakup wasn’t a bad one. Did he unfriend me because he doesn’t like seeing me happy and living life without him?
Why did my ex unfriend me on social media?
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