What is the legal ruling regarding a father who married another woman without his family's knowledge, leading his wife to leave the home in sadness and his children to feel deceived?

The mother must return to her husband's home, and it is not permissible for her to leave without his permission. Marrying more than one woman is permissible in Islamic law. The father's concealment of the matter does not justify her disobedience, her departure, or her seeking a divorce. What is obligatory is to fear Allah and to act in accordance with Islamic law. The children must strive to reconcile their parents and to honor them.