Kdramas with mature romance

I'm a fan of rom-coms but lately I felt like I'd want to watch something different. 

What I'm looking for is:

- a mature take on romance/relationship

- no fantasy/horror subplots

- no unnecessary and dragging misunderstandings

- healthy communication between leads

- preferably calm setting/vibe

- it will make my heart feel warm

Hit me up with your faves!