他の男の精液で孕むとき1＆AFTER STORY ～襖の向こうで精液を注ぎ込まれている妻～

3 years after giving birth to their long-awaited daughter Mizuho, Emi and Hideaki keep showering her with love. On the outside, they seem like a happy family. However, Hideaki is still troubled by his infertility. The married couple has been trying for a second child for a while now despite the disease, but to no avail. One day, Hideaki's brother Shuuma, Mizuho's real father, returns home for a long vacation.

To this day, Hideaki still doesn't know that Emi and Shuuma had a real affair behind his back. Maybe because of this, Hideaki asks his brother a taboo question yet again.
"Will you help us conceive a second child?"

(edited translation of the description on the official site)