He has been maintaining a physical relationship with his daughter-in-law for almost five years. (Natsume Ayaka ADN-356)

Caichun works as a manager at my company. She's not only beautiful but also very intelligent and capable, making her a perfect daughter-in-law. She's also incredibly charming as a woman, even though I know it's not right... But I've maintained a physical relationship with her for five years...