Why does this guy keep following & unfollowing me?

We were friends with benefits for a short time when we were both 16, and then I moved away and we remained regular friends, we’re now 21. Last year he got a girlfriend and she supposedly made him unfollow all women on Instagram. They broke up a couple months ago and since then he keeps sending me follow requests on Instagram (my account is private). I accept them and then a week later he unfollows me again and then re-requests to follow me another week later. It’s happened 5 times now over the last 2 months and I’ve started deleting the follow requests. And then today he sent me a friend request on Facebook. What is his deal? He knows I’m in a committed relationship so I don’t think he’s trying to get in my pants, but what’s with the following and unfollowing of my account, and now trying to get to me on Facebook?
Why does this guy keep following & unfollowing me?
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