Hey, thanks for reviving this recommendation thread, over a year later!
First, for others that are looking for that kind of hero (since it seems quite popular): I second Boss & Me where the male lead absolutely fits the description, as well as Discovery of Romance and Oh My Ghostess, although they focus a bit less on that aspect (still pretty obsessive heroes though, hehe).
@Roisina: thanks for your other three recs -- I'm currently watching Second time twenty years old again, and I get what you mean! (though he sure is childish about it, hahaha)