Meet Me Up at Somewhere in Scorpio.

"You'll never fall in love with me." Takamura, a high school student, returns to the town where he lived as a child and, by chance, finds himself in the same class as Rei, the boy he had a crush on back then. Rei also remembers Takamura, and feeling something akin to fate, Takamura once again begins to harbor a faint feelings for him. However, when Takamura witnesses Rei entering a hotel with a man after class, Takamura is surprised and asks him about it. Rei nonchalantly replies that the guy was a sex friend, and Rei's next words are: "I have no idea what it means to fall in love with someone"...?