Love Polygon

Manhattan Love Story? At one point in the show, a character actually drew up a chart to describe the love polygon, where someone fell for someone else who's in love with another person entirely and so on. The supposed "male lead" and "female lead" eventually did get together, if my memory serves me right. The drama is kinda bonkers, though. You might not like it if you're not used to Japanese dramas.

• Secret
  • The ML was in love with a girl who was killed in a hit-and-run; he is engaged to his childhood friend who he is semi-protective of but has no romantic feelings for; he hates the FL at first (believing that she was the one who killed his lover and knowingly left her to die) but later falls for her
  • The SML starts out liking the FL to a certain extent and proposes to her, later he abandons the FL and appears to like the SFL, but he always loves himself the most and looks out for his own interests first
  • The SFL is in love with the ML, but his lack of feelings for her slowly but surely harden her heart and she becomes close with the SML
  • The FL starts out in love with the SML and makes huge sacrifices for him, but eventually learns of how deeply he betrayed her; later she falls for the ML
  • Note: I haven't finished this one yet, but based on spoilers I've seen I'm 99% sure the ML and FL end up together
• Wednesday 3:30 PM
  • The FL's boyfriend dumps her at 3:30 PM on a Wednesday. She happens to read an article that says women look their most tired / worst at 3:30 PM on Wednesdays. The FL's childhood friend (their mothers were best friends) returns from abroad. He takes over running his friend's (the SFL's) coffee shop while she goes out of town, but a fire burns it down. The ML moves in with the FL and pays "rent" by taking her out for fun experiences (similar to great dates) at 3:30 PM every Wednesday so she looks super happy and refreshed at that time. They post pictures from the excursion to make her ex jealous. At this point the ML has feelings for the SFL (the coffee shop owner). The FL wants to make her ex jealous to win him back. Her ex is dating another woman in the FL's office, and the SFL is out of town. In the end, the SFL has chased the ML down and tried to trap him into marrying her. The FL's ex wants her back, and the ML and FL have fallen for each other. 
• Weightlifting Fairy Kim Bok Joo
  • The SFL, the ML's ex, wants him back
  • The FL is the ML's childhood crush and when he recognizes her they become friends and he quickly falls for her again
  • In the early part of the drama, the FL develops a strong crush on the ML's older brother
  • If I remember correctly, the older brother had another love interest
  • The FL eventually gets over her crush, and later returns the ML's feelings
• Kimi wa Petto
  • One SFL likes the SML
  • One SFL (the ML's ex) likes the ML / wants him back
  • The ML likes the FL but keeps his feelings to himself
  • The FL is very confused about her feelings; she's fond of the ML but doesn't see him in a romantic light; she thinks she likes the SML but is never comfortable around him
  • The SML likes the FL and "dates" her, but when they're "dating" the FL lives with the ML without the SML's knowledge, and later on the SML lives with the SFL without the FL's knowledge - they're both basically emotionally unfaithful to each other 
  • Eventually the FL realizes her feelings for the ML and they end up together
• In Time With You
  • The SFL has feelings for the ML
  • The ML and FL are best friends and that's how she sees him; plus they're never single at the same time
  • The ML has loved the FL since they were in high school, but is terrified of losing her if he jeopardizes their friendship so he denies his feelings and tries to date other people
  • The FL has an on-again-off-again relationship with the SML
  • The SML is a terrible boyfriend and cheats on the FL with another woman
  • Eventually the ML breaks up with the SFL and the FL breaks up with the SML, they accept their feelings for each other, and end up with each other
• Gu Family Book
  • The SML has feelings for the FL, but never reveals them
  • The FL has had a crush on the ML since they first met as children
  • The ML has feelings for the SFL in the beginning
  • The SFL eventually rejects the ML, and he later comes to return the FL's feelings