If you file as Married Filing Joint (usually the better filing status) your joint refund can be taken for his back debts. You can still file as Married Filing Joint & include the Injured Spouse Form (8379). Form
8379 is filed by one spouse (the injured spouse) on a jointly filed tax return
when the joint overpayment was (or is expected to be) applied (offset) to a
past-due obligation of the other spouse. By filing Form 8379, the injured
spouse may be able to get back his or her share of the joint refund, it can take 11 weeks for a return to be processed with the Injured Spouse Form.
If you file as Married Filing Separate your refund would not be taken for his back debt but filing separate does have its disadvantages.
With Married Filing Separate, you will usually pay more tax on a separate return, the
standard deduction is half of what a joint return is, you cannot take all the
credits you may qualify for, for ex. You
cannot take the earned income credit or the education credits, and some
deductions and credits are reduced at income levels that are half those for a
joint return, for ex. Child Tax Credit.
Married
Filing Joint vs. Married Filing Separately
https://ttlc.intuit.com/questions/1894449-married-filing-jointly-vs-married-filing-separately
When Married Filing Separately Will Save You Taxes
https://turbotax.intuit.com/tax-tools/tax-tips/Family/When-Married-Filing-Separately-Will-Save-You-T...
