Is a Muslim woman obliged to separate from her non-Muslim husband, and what is the Islamic ruling if she refuses to do so?

If the wife embraces Islam while her husband is a disbeliever, the marriage is dissolved upon the expiration of her waiting period ('iddah), unless the husband converts to Islam during that time. If the husband embraces Islam after the expiration of the 'iddah, the preponderant opinion is that he can take her back with her consent, based on the Prophet's (peace and blessings be upon him) statement: "He returned his daughter to Abu al-As ibn al-Rabi' years after she embraced Islam, when he (Abu al-As) embraced Islam, may Allah be pleased with him." If the wife refuses to separate from him, then a judicial separation must be enforced between them.