the male lead and female lead have become friend and the male lead has finally fallen for her, but he finds out that she's seeing someone so he starts to act cold and mean to her. Eventually she realizes she loves the male lead as well and breaks it off with the other guy.

Orange Days comes to mind, but it's the opposite of what you're looking for in terms of the relationship. It's the ML who is in a relationship, not the FL. Amazing drama though so I hope you watch it anyway.

 PrettyCarEye:

Orange Days comes to mind, but it's the opposite of what you're looking for in terms of the relationship. It's the ML who is in a relationship, not the FL. Amazing drama though so I hope you watch it anyway. 

Not really what I'm looking for, but thanks.

Maybe:

  • Piang Chai Khon Nee Mai Chai Poo Wised
  • Pride
  • Siege in Fog
  • More like the ML was unreasonably jealous with FL's friendship with someone else, thus FL didnt see anyone else. ML then pursues FL again realizing he was wrong:  Inborn Pair, Neung Nai Suang, wonderful life