Kono Koi wa Moto Kano no Teikyou de Oukuri Shimasu

Synopsis

When she was in high school, everyone admired Yuzuki Manami, a beautiful, down-to-earth girl. I, Hajime Kinugasa, was supposed to be her beloved ex-boyfriend....... The "fake lover" was our secret relationship back then. After our relationship has long since dissolved, what awaited us as sophomores in college is... "What are you doing here!?" It was an awkward reunion on a chat app. I had confessed my unrequited love for Yuka Shichino, a friend at my university. "I know you better than anyone," as Manami played the perfect wingwoman. But when my one-sided love with Shichino comes true, what will happen to the relationship between Manami and me? This is a slightly mature romantic comedy about longing and regret! (Source: Sneaker Bunko, translated)