Why do I get jealous over a girl even though I don't want to be with her at all?

 Yes, there are a few K-dramas in which the second male lead wins the girl. Here are a few examples:

Business Proposal (2022): In this romantic comedy, the second male lead, Cha Sung Hoon (played by Kim Min Gue), is a kind and supportive friend to the female lead, Shin Ha Ri (played by Kim Sejeong). He is always there for her, no matter what. Sung Hoon eventually wins Ha Ri's heart, and they live happily ever after.

Hometown Cha-Cha-Cha (2021): In this heartwarming drama, the second male lead, Ji Sung Hyun (played by Lee Sang Yi), is a handsome and wealthy businessman who falls in love with the female lead, Yoon Hye Jin (played by Shin Min Ah). Sung Hyun is kind and caring, and he always puts Hye Jin's needs before his own. In the end, Hye Jin chooses Sung Hyun over the male lead, Hong Du Sik (played by Kim Seon Ho).

Weightlifting Fairy Kim Bok Joo (2016-2017): In this romantic comedy, the second male lead, Seong Joon Hyung (played by Nam Joo Hyuk), is a swimmer who falls in love with the female lead, Kim Bok Joo (played by Lee Sung Kyung). Joon Hyung is a kind and supportive friend to Bok Joo, and he always believes in her. In the end, Joon Hyung wins Bok Joo's heart, and they live happily ever after.

These are just a few examples of K-dramas in which the second male lead wins the girl. There are many other K-dramas with similar storylines, so if you are a fan of this trope, you are sure to find something to your liking.