Aisai ~Tsuma to Oyaji Dake no Toki~

The protagonist, Tomokazu Mihara, lives with his beloved wife, Maho, and his father in their family home. They started living together about a year ago, after Tomokazu's mother suddenly passed away from an illness. His father initially lost the will to live and quit his job, but with Maho's support, he eventually recovered. However, as his energy returned, he began to develop inappropriate feelings towards his beautiful and young daughter-in-law. Unaware of his father's lust, Tomokazu and Maho start trying to conceive a child. They struggle to get pregnant, and Maho worries it's her fault. One day, after Tomokazu leaves for work, his father approaches Maho and offers to help with their fertility issues. He takes advantage of her vulnerability and forces himself on her. This continues, with the father-in-law pursuing Maho whenever he can, and Maho, fearing her husband will find out, being unable to resist. As time goes on, Maho becomes increasingly drawn to the intense and passionate encounters with her father-in-law.