Many people erroneously believe that when they merge lives with a spouse, they merge credit files, too. However, that's not true.

Your credit history is yours and yours alone, says Barry Paperno, consumer affairs manager with myFICO.com.

Whether you're married, divorced or widowed, your credit report contains only your accounts. That could include any joint accounts or obligations on which you're a co-signer or authorized user, but your credit history contains only accounts that have your name attached.

If you and your spouse or partner apply for something together, such as an apartment or home mortgage, your partner's credit history will be a factor, but your credit reports will not actually combine. Rather, both credit histories will be considered. With a mortgage, the worst history can have the greatest impact.