File the 8379 with your joint return. The IRS will then take only your portion of the refund, based upon computations of income and tax payments. 50/50 is not going to be the issue.
The bottom line is that the form 8379 DOES provide relief. Note that a similar approach may be available for your state tax refunds.
Of course, the best view is to plan your withholding so that you have little or no refund and it becomes a nonissue.
Marty Davidoff, firstname.lastname@example.org, 732-274-1600. This answer is provided for general information only. You should seek advice from an attorney or tax professional.
Form 8379 is the correct form. If you complete and file such with your tax return, the IRS will only keep your portion of the refund. There is no state income tax in Washington, so that is not an issue. In the future, you and your husband should plan your withholding, so you have little to no refund - minimizing the effects of this issue. If you need help resolving the past liability, I am in your area. My number is (425) 451-9572. Best of luck.