What is the ruling on children going to their stepmother's house without their mother's consent?

Understanding should prevail between spouses, and actions should be guided by what serves their best interests, preventing Satan from creating discord between them. Indeed, one of Satan's greatest goals is to separate a man from his wife. Jurists have stipulated that child custody is a right for both parents jointly while the marital relationship exists. Therefore, your husband is not permitted to take the children to the second wife's house without your consent. However, if there is no fear of harm to them, it is better not to make this issue a source of conflict. We hope that your husband will consider your feelings and not take them without your consent. You are not permitted to seek a divorce solely for this reason, unless there is a legitimate شرعي justification. If the children are within the age of custody, their interaction with each other is not prohibited, unless there is a fear of some mischief, and the father should be advised to take this into consideration.