Theory of Love (2019)

Third is a filmology major and a member of the Savage Team along with his best friends Two, Bone, and Khai, but he has a secret. Third has been secretly in love with Khai for years. For three years, he has kept his love a secret in his heart, silently supporting and loving Khai while knowing there is absolutely no future between them since Khai is as straight as a streetlight pole and also an absolute player. To make matters worse, Khai has a "no dating friends" policy. How long can Third love Khai silently while watching Khai bring a different girl home every night? Third has tried to see Khai as just a friend. But has failed time and time again. Because as easy as it is to fall in love, to stop is just as hard. Maybe even harder. That is until Third learns a secret that breaks his heart completely. But when Third decides to stop, Khai decides to start. (Source: Soju at MyDramaList) ~~ Adapted from the novel "Theory of love" (ทฤษฎีจีบเธอ) by JittiRain.