Here is what to do with a wife who wants to leave Islam.
Muslims are very cruel and evil to their own people, so we should not be so shocked when they kill us. It is just a way of life for them.
"[al-Mumtahanah 60:10]
i.e., If he has a kaafir(non-Muslim) wife, it is not permissible for him to stay married to her. He has to advise her and establish proof against her, then leave her. If he is in a place where there is an Islamic government and shareeah law, then he has to refer her case to the Muslim qaadi, for him to ask her to repent. If she does not repent then the ruling of Allaah should be carried out on her, which is execution, because the Prophet (peace and blessings of Allaah be upon him) said: Whoever changes his religion [leaves Islam], execute him.