Why is he lurking?

So, I recently made a post about my ex. He tried to add me on Snapchat last week and i declined it. Then, my best friend, told me he recently watched her Instagram story. He does not even follow her… and she does not follow him. He has a NEW girlfriend who he has been with since August and this is his 7th one since being out of jail. It’s complicated between us. But he cut me off last April. Im just confused why is he lurking on my friend’s Instagram and trying to add me on snapchat?
Why is he lurking?
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