Based on the adult manga by Konomi Shikishiro.
It's a seemingly happy marriage for Shuu and Haruka. Two years into their bond of love, Haruka decides she wants conceive a child with her husband and raise a family. Unfortunately for the two of them, Shuu is suddenly unable to perform in the bedroom. According to Shuu's doctor, there's nothing physically wrong with him, leaving the problem being something potentially psychological.
In fact, there is something hiding away inside of Shuu's mind that's affecting his performance; a fetish that he's only hinted at to Haruka.