Guy's Behavior

Why is he trying to get my attention all of a sudden?

So me and this guy were a thing and stared talking a few months ago but it didn't really end up going any further, so he stopped talking to me completely (stopped saying hey and even avoided me at school) But now I've been texting and talking to one of his friends. The friend told me that the guy I was talking to, his friend, was okay with it. And now, all of a sudden, the guy I was talking to has started showing up again. He's been by my locker to say he to me between almost every class and he keeps trying to get my attention. Why now?
Why is he trying to get my attention all of a sudden?
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