Is not the husband's insertion of his fingers into his wife's vagina on the wedding night to verify the hymen—which causes physical and emotional harm—considered a mistreatment of the marital relationship, thereby permitting the wife to refuse him?

There is no definitive ruling on the prohibition of the husband's mentioned action unless it causes harm to the wife, based on the Prophet's (peace be upon him) saying: "There should be no harm nor reciprocating harm." It is obligatory for a woman to obey her husband in matters of enjoyment within what is recognized as good (ma'ruf). However, anything that goes beyond the bounds of natural disposition (fitra) and harms her does not necessitate her obedience, based on the Prophet's (peace be upon him) saying: "Obedience is only in what is recognized as good."