stepmother of lust

As a mother, Ayaka is confused as to how she should interact with her husband's stepchild, who is closed-minded and mute. In the midst of all this, she finds her son's homeroom teacher, Kosaka, who came to visit her home, and her husband, devouring each other's bodies. Ayaka felt so frustrated by her husband's betrayal that she agonized, but all she could do was bite her lip and endure it. One day, Ayaka gets a call that her son was peeking at girls changing clothes at school. Kosaka comes to her house and relentlessly blames Ayaka, but...