It would not directly hurt your credit, if you are not a party to the loan. It will indirectly hurt you, however; when people are married, if they look for  a major  purchase or loan (e.g. to buy a car; to buy a house or refinance a mortgage), lenders, sellers, etc. will look at the credit of *both* of them, based on the reasonable and realistic view that if one spouse is a credit risk, that may impair the ability of the family as a whole to pay, since the credit risk spouse might incur additional liabilites, default on debts, manage money poorly, etc. Therefore, while your personal credit score will not be affected by a default if  you're not on the loan, if you are married  to someone with damaged credit, that will have implications  for you.