Sekaiichi Hatsukoi 2

Synopsis

Shouta Kisa and his perfect boyfriend Yukina haven't been able to see much of each other because of Kisa's work. Yukina always complies with Kisa when he says he is busy at work, which causes Kisa to believe that Yukina's lack of anger means he doesn't love Kisa as much as Kisa thought he did. Kisa finally resolves to make time for Yukina no matter what after he hears about the marriage of a friend of his when a major project was given to him from Takano. Again, Yukina says it is fine when Kisa can't make it, but Kisa goes to his work and waits for him anyways after hurrying to finish his work. There, he unexpectedly finds Yukina meeting with a girl and watches them as the two walk towards the naughty part of town Kisa knows all too well.

(Source: Wikipedia)