My Girlfriend's Mom: The Day I Became My Girl(2017)

Original title: 내 애인의 엄마: 내 여자가 되던 날

Koyuki, disliked by her young and beautiful stepmother, has a passionate love affair with her boyfriend Josuke at home. However, while Josuke is with Koyuki, he keeps thinking of her mother, who has a rich and mature taste. After that, Josuke, who was sentenced to break up with her Koyuki, unconsciously remembers her Misae and goes to find her.