Does she have to leave her husband if he does not become Muslim?
Question

                Does a woman have to leave her kaafir husband if she becomes Muslim? What is the ruling if she refuses to leave him?.
Praise be to Allah.
    If a woman becomes Muslim and her husband is a kaafir, then 
    the marriage is annulled, but she may wait until the ‘iddah ends, then if 
    the husband becomes Muslim during that time, then she is still his wife, but 
    if he does not become Muslim before the ‘iddah ends, then the annulment of 
    the marriage becomes clear, starting from the time she became Muslim. 

    Can he go back to her if he becomes Muslim after the ‘iddah 
    ends? 

    There are two scholarly opinions concerning that. The more 
    correct view is that he may go back to her if she agrees, because the 
    Prophet  (peace and blessings of Allaah be upon him) sent his daughter 
    back to Abu’l-‘Aas ibn al-Rabee’ several years after she became Muslim, when 
    he also became Muslim. 

    But if she refuses then they must be separated by force by 
    the judge. End quote. 

    Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him)