My affidavit of support didn't file taxes in 2010

If the USC or LPR petitioner sponsoring you does not meet the Affidavit of Support's financial requirements, then the petitioner must get a co-sponsor to also file an affidavit of support, in addition to the one which the petitioner must file, IRREGARDLESS of whether he meets the financial req's or not and whether previously filed tax returns or not. For your information, providing only last year's tax returns is enough when one meets the financial requirements, no need to provide 3 years worth..

If you have any doubts about whether your sponsor meets the affidavit of support requirements on his own, consult with a qualified immigration attorney before filing. The sponsor must file an I-864 whether they meet the income requirements or not, but if not, then the petition or application must also be accompanied by an I-864A from a co-sponsor who does meet the income requirements of 125% of the poverty limit for the relevant household size. If you are not sure how to interpret these rules it is critical to review them with counsel before filing anything with USCIS.

This would not be autimatically done. Tax amounts must generally be provided, although only the last years return need be submitted.