Ikenai Kozukuri ~Shin'yuu no Okaa-san ni Tanetsuke Shimakuru Isshuukan~

In a moment of weakness Ritsu gets the beautiful housewife Sagamiya Yura to betray her husband and have sex with him. Declaring his love for her and his desire to marry her and have children she says that it's impossible. Desperate he begs her to at least let him try and make her pregnant while her husband is away on business. If he succeeds then their relationship is approved by God. He now has one week to make her pregnant before her husband returns.