[Ruling on the Divorce of One Compelled by His Wife to Divorce]

Answer—and Allah is the One who grants success: The divorce of the one compelled does not take effect if he had no intention to divorce. This may be supported by His—Exalted is He—saying: "Except for one who is compelled while his heart is secure in faith." [Al-Naḥl:106], and by what is narrated from the Prophet (May Allah bless him and his family and grant them peace): “My ummah has been absolved of error, forgetfulness, and what they are compelled to do.”
The commoner’s belief that divorce has occurred does not alter our statement that it has not occurred. It is narrated that when ʿAmmār (May Allah be pleased with him) spoke the word of disbelief when the idolaters compelled him to utter it, he was greatly distressed and thought he had impaired his faith. Then the verse we have cited was revealed—His saying, Exalted is He: "Except for one who is compelled while his heart is secure in faith; but whoever opens his breast to disbelief…" [Al-Naḥl:106]—clarifying that there is no sin upon one who speaks the word of disbelief with his tongue under compulsion, without acceptance of disbelief and without intention. Allah—Glorified is He—thus nullified the ruling that would normally follow from uttering the word of disbelief when under compulsion; and there is no doubt that uttering the word of disbelief is weightier and graver than uttering divorce.
If it be said: This compelled commoner thought his divorce had occurred; the “divorced” wife also thought it had occurred, as did her guardian; after her waiting period elapsed, the woman remarried; thereafter, her first husband sought a legal opinion and the muftīs ruled that the divorce had not occurred. What should be done? What is required of all involved—the guardian, the woman, and the husband?
We say: In such a case, all must return to a just judge—if one exists—or to a sound, upright scholar whose judgment all agree to accept. All parties should litigate before him, present whatever they have concerning the case, and then all must act upon and adhere to what the judge or scholar rules.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1