Same question was put to Imam Jafar Al-Sadiq (AS) by Christians and Jews: Why Muslim men are allowed to marry women who believe in Moses and Jesus (temporary marriage) but men who believe in Moses and Jesus are not allowed to marry Muslim women at all? Imam (AS) replied: Muslim men are allowed to marry women who believe in Moses and Jesus because Muslims also believe in Moses and Jesus as prophets, but men who do not believe in Muhammad as a prophet are not allowed to marry a woman who believes in Muhammad.
Marriage between a believer woman and non believer man is not permissible at all. There is no exception in this definite rule. It is a matter of protecting the faith of the Muslim woman to keep her away from being under control of a man who does not believe in Islam.
Quran is very clear that it is not permissible for a Muslim woman to marry or even to continue marriage with a non Muslim man (Sura Al-Momtahana , verse 9).
The Prophet (SAWA) has ordered all women who embraced Islam to immediately leave their non Muslim husbands.