Why did my ex follow my cousin?

Okay I had this ex situationship and everything ended because he got jealous of my guy best friend. So it’s been 6 months after that. And, he recently followed my cousin. He knows who she is because I would post her and I would tag her and he waited until now to follow her. And, i feel bothered by it. I don’t have any feelings for him anymore it’s just weird.

Why did my ex follow my cousin?
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