It's actually pretty common to be asked those type of questions pretty much anywhere when you hit a certain age. Plus, romance and love lives are usually a pretty fun and exciting topic of conversation among friends. However, if you and your friends don't really involve yourself in love and dating then it probably won't come up.
I get what you're saying, but I was just saying in general. I agree it's not anyone's business, but people do like to ask about that stuff because knowing about someone's love life is exciting to some. I personally don't get those questions because I'm not at that age yet and am not surrounded by people that date lol

is it just a korea thing where everyone is so hopelessly obsessed with each others dating lives and relationship status'? Is it just a trope in all of these stories with romance elements between the main character and their friends or acquaintances or is this like a real reflection of the social culture over there. Or maybe it's like this everywhere and I've just never met anyone who barrage the people around them with endless questions about who they're with and when they're gonna get serious.