Kdramas with mature relationships and/or with sex

Some people watch Kdramas because they find them "clean" and that's okay, however sometimes I prefer dramas where the characters have a realistic relationship to physical affection and/or sex, ie it's a thing that exists in their world and/or they might even be doing it. This list is to help people like me who find that the taboo about sex in Kdramas can be a bit unrealistic and ridiculous, and who like having more realistic characters (and not wait for 16 episodes just to have the main characters peck on the lips with eyes wide open). It's not about having Game of thrones' style of gratuitous full nude sex scenes ; it's about putting a bit of realism when it comes to telling the stories of 30-something characters.

FULL DISCLAIMER : I haven't watched all of them yet so I can't always speak to the quality of those shows.