Absolutely not
I’ve never heard of a lender requiring this. Lenders will accept your individual application for credit even when you’re married.
There are however situations where YOU may want to apply for new credit as a couple rather than individually. For example when a non-working spouse needs to apply for a new credit card or a car loan.
Another example is when YOU want to both your income to be used, such as when applying for a mortgage, because applications with household income is more robust vs. a single applicant income when calculating debt-to-income ratio. In this case however, this requires both parties to be on the application and that means that both credit reports and scores will be pulled for both applicants and you’ll both be legally contracted for the loan if approved.