The Smile Has Left Your Eyes (2018)

Both dramas involve a family secret and a crime investigation. Both male leads have grown up as orphans and experienced difficult childhoods. They are both seen as weird and off-putting by others and the FL's are the only ones that understand their true personalities. Jung So Min also stars in both dramas!

The relationship between the leads is very understanding and mature. There’s some miscommunication as well, but not of the type that makes it unrealistic. Their situations make it plausible for them to react that way.