People will talk with their friends about this. It depends on the person and the closeness of the friendship. It also depends on a person's beliefs, how they are raised, and their individual personality. Not everyone does, and and so don't feel that you have to announce and discuss every intimate detail with your friends if you are not comfortable with it.

Yes, pretty common but not everyone does

It's very common in the US, especially among younger people. University age people are somewhat notorious for having little sense of propriety. Korea is a far more conservative country, and it's the opposite for foreigners in Korea. They tend to not understand the subtle nature of relationships and try to be too public which makes people uncomfortable. Though it's common, I think it's a bit gossipy. There were old proverbs that seem to go unremembered these days which touched on this behavior. "A gentlemen never asks and a lady never tells." and similar things.