One of the requirements for becoming a U.S. citizen consists of showing good moral character during the period covered by the residency requirement, which is usually five years. An extramarital affair during that time might show that you lack the necessary moral character to become a citizen, but this is not an automatic bar to citizenship. The USCIS official will follow up on evidence of an affair to determine whether it broke up your marriage, or whether your spouse knew about it and accepted it. (Formerly, USCIS considered an extramarital affair to be automatic evidence of bad moral character, but this rule no longer applies.) If USCIS determines that the affair showed bad moral character, you will be eligible for citizenship five years after the end of the affair or the date of your divorce, whichever happens sooner.
USCIS is less likely to find that an extramarital affair shows bad moral character if you were not living with your spouse at the time of the affair, if you had an open marriage with your spouse, or if your spouse otherwise was aware of the affair and accepted it. Cheating on a spouse by conducting an affair without their knowledge when you were living with them likely will lead to a finding of bad moral character. A foreign national may be able to persuade USCIS that the affair should not block them from citizenship if their marriage survived the affair, and they are still living with their spouse. Also, they may have a strong argument if the affair did not occur until they were in the process of getting a divorce for unrelated reasons. If your marriage ended due to reasons unrelated to the affair or other misconduct by you, USCIS probably will not hold the divorce against you.
Discovering an Extramarital Affair
You might wonder how USCIS ever would find out that an affair occurred. Form N-400 does not ask questions about affairs. In most cases, USCIS will find out about an affair when an applicant lists their children on Form N-400. They must include children from extramarital relationships, if any, as well as the date of birth of each child, where they were born and where they live, and any gaps in supporting them. You do not need to disclose the other parent of each child. USCIS likely will follow up if you have two children who were born less than nine months apart, or if one of your children does not share your last name or the last name of your spouse.
Another red flag arises when a divorce decree does not provide for the support of a child who was born before the divorce. The decree might even state explicitly that a certain child is not the child of the couple. When USCIS reviews the divorce decree, it may notice this type of discrepancy and follow up with the applicant.
Form N-400 does require an applicant to show that they have kept up with any child support payments as ordered by a court. USCIS may find out about an extramarital affair if it discovers that you were ordered by a court to pay child support for a child born to someone other than your spouse at the time. As this example and the others show, USCIS most often finds out about an affair when it produced a child, but this does not mean that the affair will not be revealed if no child resulted from it.
Divorce for Unrelated Reasons
If you divorced your U.S. citizen spouse for reasons unrelated to an affair or other misconduct, this should not affect your eligibility for citizenship. This is true even if you got your green card on the basis of your marriage. Generally, the only negative effect of the divorce is that you will not be able to take advantage of the three-year residency requirement for citizenship. This option is available only if you are still married to your spouse and living with them. If you are not, you will need to wait five years before applying for citizenship.
Sometimes a USCIS officer who is reviewing an application by a divorced foreign national will want to make sure that they entered into their marriage with the U.S. citizen in good faith. Immigration fraud, such as a sham marriage, is a basis for denying citizenship and deporting the foreign national. You may need to submit additional documents to convince the USCIS officer. These may include mortgages and bank accounts held with the U.S. citizen spouse, birth certificates of any children, or any evidence of going through couples therapy or taking other steps to try to resolve the problems with your marriage before getting the divorce.