Yachin Hanbun no Ibasho desu.

Shiraishi, a diligent college student who is always smiling, is troubled by concerns about his boyfriend's infidelity. He confides in his coworker, Kanzaki, and eventually agrees to Kanzaki's suggestion to live together. While Shiraishi initially sees the arrangement as a simple favor, he begins to realize there may be more to Kanzaki's intentions than he first assumed.