I would not expect IRS to understand the reasoning behind each of them paying back only half the EIC which should not have been claimed.  I would not be surprised if they charge both of them for the total amount, and take it out of the $1,400 for each.  I think I would file two original 1040's, mark both of them "amended" across the top, and attach an explanation cross-referencing each name and SSN, with a copy of the marriage certificate.  And then wait a year for the returns to be processed. If they want to make a side deal regarding who pays the EIC refund, hopefully they are still married by the time it needs to be worked out.