Is it permissible for me to take back my wife, whom I divorced due to my parents' desire, with their threat to sever family ties if I take her back?

If the parents' prevention of their son returning to his wife is for a valid reason, such as a defect in her religiosity or character, then obedience to them is obligatory. However, if there is no justification, then obedience to them is not binding, and this is not considered an act of disobedience. But if there is no harm to you in not returning to her, then obeying them is preferable. You must treat them with piety, kindness, and obedience in what is good.