10 dramas/movies with ____? #4

10 dramas where a character's friend/sibling dates/sleeps with their ex (I would love if y'all could give one or two lines providing the tea hehe)

 Ahn Sarang:

Character's friend/sibling sleeps with character's ex? Or with their own ex? 

from what i understood A is friends/sibilings with B and B dates/sleeps with A's ex

1.Mr. Swimmer
2nd ML is the ex of FL,2nd ML and ML are friends,ML and FL date each other.

2.As Beautiful as You-FL's Ex and her best friend started dating behind her back. FL found out on her birthday

3.Adult Trainee-   FL finds her ex-boyfriend is dating her best friend. She  decides to start fake date her childhood friend to prove she was okay with it even though she felt hurt 

 NoirRoseHeart:

Does it have to be their ex at the time, or could the character still be dating the person and then the friend/sibling sleeps with them causing them to break up/become the ex?

I meant ex at the time but I will count this too :)

Next count starts at 4

5. Sud Sai Pan (2013) - FL, her twin sister, and ML. FL started dating the ML after the ML and her sister used to be a couple. However, FL didn't know she was a twin (even had a sister) and ML thought the FL was the FL's sister.

BONUS since it is a movie, but Must Date the Playboy. FL's best friend dates the ML, but they break up. The friend asks FL to date ML for revenge, but the ML and FL fall in love with each other. 

7. Suspicious Partner - ML's gf cheated on him with his bf and that ended both romantic relationship and friendship

8. Perfect Revenge Marriage - FL stole her adoptive sister's fiance. Does this count?