Hitozuma Koukan Nikki

Kouichi lives a happy life with his wife, Kanako, and daughter, Nao. But one day, Kimihiko, his neighbor, says to him, "Do you wanna fool around with a married woman?" "What?" What Kimihiko suggests Kouichi is to swap their wives. Kouichi doesn't take it seriously at first, but....
(Source: ErogeShop)