young mother

The protagonist"s girlfriend has a wide social life, and he initially thought she was just going to have a casual fling, but she insisted on marrying him. One day, she brought him home to meet her parents. After meeting her beautiful mother, he negotiated and finally agreed to marry her and have a son. Soon after, his girlfriend, who he thought was married, started fooling around again. Her mother caught her and scolded her, leading to her running away in anger. The protagonist had always coveted his beautiful mother-in-law, but never had the chance. Then, he unexpectedly ran into his former cram school teacher, and their old feelings rekindled, leading to their affair...