I did that when my ex and I broke up. It was really hard not to, I felt obsessed and like I wasn't complete unless I saw him update a status on anything, even if what I saw was something I didn't want to see. It's unhealthy though, you should try to move on.
Not my ex's, but i go through guys i used to talk to social media sometimes just to see who their talking to. i try not to but sometimes if its late at night and im trying to sleep my hands just start going through twitter
once I dump them I never check for them, although this one time I saw a friend of a friend tagged in the same picture as an ex so I was tempted to look at more of his pictures but I closed that tab a minute later because I had no interest in knowing where he is or how he's doing
I do it the whole time. Kind of pressed how we got separated tbh. His twitter link is on my frequently visited website
But he tweets funny things so I don't mind.