ML likes another girl at first, that girl can be SFL or supporting character, it doesn't matter or someone from the past.

and the girl whom the ml likes has a significant portion in the storyline

ml ends up with fl


ps : i have seen many dramas where like the sml takes more than half of the series and i wanted something reversed

any country any language (aisan , non asian) any will do

Bulgasal 

Remolove

Backstreet Rookie 

If you don't mind movies, then Rurouni Kenshin

  • ItAewon Class
  • Full House
  • My Name is Kim Sam Soon
  • My Girl
  • Padiwarada
  • Fated to love you
  • Another oh haeyoung
  • My First First Love
  • +1 Itaewon Class (but the girl isn't a SFL or a supporting character)
  • +1 Itaewon Class
  • Who Are You: School 2015
  • Mr. Queen
  • The Story of Ming Lan
  • Wednesday 3:30 PM
  • A Piece of Your Mind
  • Tempted - The ML at least thinks he likes the SFL for a good while, and he approaches the FL (as part of a bet that he can seduce her) in an attempt to prove it
  • In Time With You - The ML and FL are best friends. The ML has had romantic feelings for the FL since high school, but does not pursue them for fear of losing the FL. They both try to date other people and it goes badly for both of them.
  • She Was Pretty - The ML develops a crush on the FL as a kid before moving abroad. When he returns, the FL sends her friend to meet him in her place and the ML starts dating the FL's friend thinking she's the FL. Meanwhile when he meets the FL he is annoyed that such a person shares a name with the woman he likes and is a jerk to her. Over time he finds himself sort of falling for her (without realizing that she's actually his first love), which annoys him further and makes for hot-and-cold treatment. I won't spoil the rest. Long story short, the ML thinks he likes the FL's friend for a while because she pretends to be the FL.

Dramas where the ML is Emperor and already married to a woman that he respects (to a degree) and cares for (... to a degree) before he meets the FL: