Hi James, in that situation, Married Filing Joint (MFJ) will most likely be the best filing status.
As this article explains, "Tax filing status does not affect who completes the FAFSA" How Does Income Tax Filing Status Affect Student Aid?
The Free Application for Federal Student Aid (FAFSA) instructions details various scenarios for married parents who are separated: FASFA- Reporting Parent Information
This TurboTax article explains the consequences of the Married Filing Separately status, the most detrimental would likely be the ineligibility for education credits such as the American Opportunity tax Credit: Should You and Your Spouse File Taxes Jointly or Separately?
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