Mitsuka, Volume 4 (manga)

Twenty-four-year-old Reo is a popular host with women - and also very straight. When he's approached by thirty-four-year-old sex-worker Takahiro, he somehow finds himself addicted to the feeling of being with him. They even move in together so they can be together every night.

Nevertheless, both of them are constantly aware of the fact that Reo identifies as straight, so the relationship has to end eventually...