I marry my wife in another country and brought her to america. Now we are divorce for 3yrs and then she moved out do i need to pay her rent n utility

Sponsorship under form I-864 affidavit of support is regarded as a contract between you and the U.S. government in which the person sponsored is a third-party beneficiary. Under part 8 of the I-864 called the "Sponsor's Contract", "You agree that, in deciding whether the intending immigrant can establish that he or she is not inadmissible to the United States as an alien likely to become a public charge, the U.S. government can consider your income and assets to be available for the support of the intending immigrant." You are to provide the intending immigrant "any support necessary to maintain him or her at an income that is at least 125 percent of the federal poverty guidelines." For a party of one, that amount would be $13,962.50 under the 2012 poverty guidelines. Although you are divorced, the contract follows you and can only be broken upon your ex-wife's naturalization, death, permanently leaving the U.S., having 40 quarters of earnings in the U.S. (10 years), or becoming subject to removal but being able to gain a new grant of adjustment of status in removal proceedings based on a new affidavit of support, if one is required.