A married couple who had been friends since childhood. They have problems in having kids because of the husband who can't maintain an erection and is less experienced in sex. 
 
(Source: Nekopoi and Has Been Translated)

After two years of marriage, Shuujirou and Haruka shared a marital lifestyle anyone would be jealous of. To outside observers, they seemed so happy together and had the perfect marriage. However, behind closed doors, Shuujirou's sex drive has stalled and Haruka doesn't know what she can do. One day, a twisted desire comes bubbling to the surface that shocks Haruka to her core as Shuujirou utters these words, begging on the floor: "I want you to sleep with another man."
 
(Source: Fakku!)
 
Notes: 
-A live-action AV with 3 part adaptation (LPNT-002-004) was released on April 2, 2018.

Shuujirou Izumi