Family is crucial for the development and health of children. Parental disharmony and quarrels before or after divorce can negatively affect children's development and health; therefore, we strongly suggest that physicians should question the interparental relationship when evaluating a child. Marriage, which forms the basis of the family, has been accepted as the only legitimate relationship in all Divine religions that allows men and women to create their privacy and share space and contribute to the continuation of the human race. Since ancient times in all cultures and religions worldwide, interparental fidelity has been the most important thing in marriage. Happy family life is perpetuated through confidence between husband and wife and heartfelt respect and love. Immodest dress and free-and-easy behavior destroy confidence and spoil mutual respect and love. Therefore, religion has established the rule of marital fidelity. The definition of adultery in all religions consists of very similar elements. Men and women who commit adultery have been punished in various ways. In this article, we discussed marriage and marital fidelity, which determine the course of the interparental relationship, from a religious perspective to draw attention to the importance of the family institution in child health.