Hitozuma ga Wakai Juuyoku ni Otosareru Toki by Tamakuro - Adult Sex Game

Machida is an ordinary family. Tsuyoshi's husband, Haruka's loving wife, Satoshi's schoolguy son.
Everything changed when the husband's younger brother died in an accident with his wife, leaving his son Masato without parents.
Machida adopted a guy. He was about the same age as Satoshi, but already looked quite mature and strong.
Life began to improve little by little, and Tsuyoshi went on a business trip.
Masato, who seemed to be just waiting for this, confessed his unworthy feelings to Haruka.
Surprisingly, the woman accepted them. She has not experienced the joy of sex with her husband for a long time,
and the love of a young guy was like a breath of fresh air.
From that moment on, the two of them had a dirty secret. The desire grew stronger
and even the presence of her husband in the room could not restrain the lustful impulse of the lovers.
The relationship that went so far changed Haruka's life as a mother and wife forever.