When you apply for a mortgage loan together the Lender will use the lower of the credit scores for qualifying purposes. That having been said, Lenders have the ability to run a "merged" credit report for married couples in the event the credit score isn't the problem, but insufficient credit history of one partner is the problem.
Get a referral to a Local Mortgage Banker with at least 15 years experience. Meet your Mortgage Banker in person to complete a thorough Prequalification. You'll find the answer to your question right there.