Shen Sinian actually didn't know why Gu Sui could be so heartless. In a relationship, he was the one who confessed first, said he liked him first, said he loved him first, but he was the one who finally broke up. In fact, he didn't understand what it meant to like someone at first, but Gu Sui left before he could teach him...
Gu Sui was admitted to his high school because he liked Shen Sinian. In the third year of high school, he got his wish and got together with Shen Sinian, but only literally. Gu Sui didn't understand why Shen Sinian agreed to be with him but then ignored his love and was unwilling to give his own love. Three years of such love was too tiring. Even he felt that such love had become too cheap, so cheap that he couldn't even look down on it...
Concept: Love is difficult to understand