Kimi ga Warui Koi no Hanashi

At the start of the new school year, high school student Hiromu is seated behind Takurou. Hiromu, who has a complex about being gay, comes out to Takurou and says "I might fall in love with you," hoping it would stop the other boy from trying to get closer to him. However, to his surprise, Takurou responds by asking him out...?! A deeply resonant love story between the most popular boy in class and the class wallflower.

(Source: Shinshokan, translated)

Note: Includes one extra chapter.