Hoka no Otoko ni Dakareru Koibito ~Tanin Bou ni Tsuranukareta Sono Koshi wa Kairaku o Motome Ookiku Futteiku~

Kazuya Shundo has a girlfriend named Miho Ichinose. The two grew up together in a rural town since childhood, but Kazuya, who didn’t like it there, went on to attend college in the city. They are now in a long-distance relationship. He dreamed of taking Miho away from there and living together once he could support himself.

However, when he returned home for a university break, an elderly man—a benefactor who had looked after Miho after her parents’ death and who served as the community leader—brought up the idea of passing on his status and fortune to the man who would become Miho’s husband. But the method involved an ancient local custom: to test their fertility, Miho would have to sleep with two prospective suitors, and then choose one of them. Kazuya was selected as one of those men. But since this would mean allowing Miho to be with another man she didn’t know, Kazuya naturally objected. Miho, however, didn’t want to cause a conflict by defying the elderly man who had taken such good care of her. So she suggested that she and the other man cover for each other and pretend they had gone through with the custom. Of course, they wouldn’t actually do anything, and in the end, she would choose Kazuya.

The other man who had been chosen was Keiji Natsuki, a senior and the second son of a local construction company, but when they actually talked, he revealed that he didn’t believe in such customs either and had no interest in them, so he agreed to go along with the cover-up.

With a solution in sight, Kazuya returned to the city to attend college.
Later, it seemed their cover story had gone smoothly, and Kazuya breathed a sigh of relief.

However, what was happening to Miho, who had been away at that time—

[Translated from DLsite]