Romance with couple that starts cute/funny but turns angsty later on

Preferably feature some life-changing event that alters one or both's personality, and that cause them to intentionally hurt each other for reasons like revenge or they turn to be enemy etc, not just some obligatory separation caused by noble idiocy that usually present at drama climax. Any country or genre's fine. No BL/GL. Example on top of my mind is the side couple Minwoo and Mijoo from kdrama Giant.  Thanks!

• The Princess' Man
• Queen for Seven Days
• Moon Lovers: Scarlet Heart Ryeo