Ura Mansion Hakkin

The protagonist of the game is an ordinary Japanese man who lives together with his pretty wife Harunako. Two years after their marriage, they decided to move into an apartment in the suburbs. Everything seems normal when the couple arrives. But very quickly they both become involved in sexual intrigues, and witness strange events - mostly of sexual nature - that occur in the presence of their neighbors. Looks like the quiet family life they were hoping for will never become reality...

[Edited from Moby Games]