The theological discouragement to marry a mushrik (polytheist) is an Islamic strategy to preserve the existence of the marriage institution and allow Muslims to better achieve the aims of their faith.
Interfaith marriage is one amongst the most fundamental sinful actions in Islam after shirk, rebellion against parental authority and killing a person without any legal reason.
Theoretically, via the good manners of a Muslim husband, his spouse may be induced to convert to Islam.
Forbidding Muslim women from marrying non-Muslim men can also be viewed as a political strategy, because if a woman is under the influence of a non-Muslim husband, she may leave Islam for his religion and their children may not be raised as Muslims.
This interfaith marriage problem may be solved by conversion of the person from other faith to Islam.