No, your spouse’s bad credit will generally not affect your finances, but there are some exceptions to the rule.
When you get married, or if you’re already married, your spouse’s credit score will not affect your credit score. Your credit score is recorded and monitored separately from your spouse and will not become jointly monitored due to marriage.
Your spouse’s bad credit only affects your finances if both of you open a joint account (if the lender reports to the credit bureaus). Additionally, if there is a joint application for a loan (car, mortgage, etc.), both credit scores will be checked. This can create problems as people with poor credit generally have higher interest rates, which can affect your finances in the long run as it costs more. To avoid this, the partner with better credit can apply for loans and financing individually.