Critter#2's answer is correct.
That said, there are accepted ways of allocating the refund (and that's what divorce lawyers do). None of the ways are really simple. But, one simple way is by income. If your husband has 75% of the income; then he gets 75% of the refund.
Where the IRS has an offset claim against one spouse (back taxes, unpaid student loans or child support) they actually have a form to allocate the refund <a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/f8379.pdf">https://www.irs.gov/pub/irs-pdf/f8379.pdf</a>
