beloved enemy drama

Hi,

Please suggest a drama in which the hero and the villain have a story together. 

It would be great if they are former friends and still have moments in which they remember that there was a time they kind of loved each other, which influence their behaviour.

2 examples: bridal mask and rookie agent rough

• Hello Monster
• The Eternal Love
• The Imperial Doctress
• Descendants of the Sun
• Go Go Squid!
• Cheese in the Trap
• Lupin no Musume
• Queen for Seven Days

Former friends:

• Cross Fire
• My Country (haven't seen this one but it sounds like it matches what you're looking for)

Have a past together:

• Memorist
• The Game: Towards Zero