I'm Looking for drama Any drama where ML is ALREADY dating FL but still has feelings for an ex.

things to clarify 

  1. I want a drama where ML and FL love each other, and are already in a relationship/marriage or whatever but ML still has some lingering feelings for an ex
  2. this ex could be dead, alive, or married to someone else.
  3. the EX does not have to be an EX, she could be someone ML liked one sided- ly ( eg : only just married but i don't want recommendations like this because here the ML and FL, even though married weren't in a relationship)
  4. there are many dramas where ML likes someone else first/hasnt moved on from ex but FL chases him. and he slowly falls for FL. this is not what i am looking for. What i am looking for is, ML is already involved with FL and is genuinely interested in her. but There are some lingering feelings in his heart for someone he loved before. (eg : Do You Like Brahms? )

Rebel: Thief Who Stole the People might work (ML's first love is alive and he's in love with/married to the FL but all his interactions with his first love felt like there was some lingering feelings, at least to me). 

Maybe Faith (ML's fiancée is dead and he clearly loves the FL by that point of the story, but still basically tries to commit suicide to both protect the FL and to reunite with his first love before he "forgets what she looks like). 

Also, possibly The Forbidden Marriage (ML seemed a bit conflicted to me and both in love with the FL and still in love with his dead wife).