You may be one of the many current illegal immigrants in the most legally difficult category -- you secretly crossed the U.S. border with no immigration documents, such as a passport with a visa stamp showing how long you could stay. You have always been at risk of being deported by ICE, even after your marriage to a citizen, because you cannot legally obtain a green card signifying permanent legal resident status often granted to immigrants who arrived with the correct legal paperwork.
Your divorce proceedings are separate from immigration enforcement. You or your citizen spouse can file for divorce in a U.S. court. You use the same divorce filing forms divorcing citizens file. A court can award you child custody, child support and spousal maintenance, even if you are known to be an illegal immigrant. If you are not the custodial parent, you may be required to pay child support and spousal maintenance to your citizen ex-spouse. The divorce court will not contact ICE about you.
However, once your marriage ends, you continue to risk being deported if ICE discovers you are an illegal immigrant, for example, if you make contact with police during a minor traffic accident or you are turned into ICE by someone who is aware of your illegal immigrant status. If you are arrested by ICE and have custody of children from your previous marriage, you may have to choose between taking your children with you to your native country or giving custody of them to your ex-spouse. You will be legally barred from returning to the U.S. for up to 10 years.
If your marriage has not become abusive or otherwise dangerous to you and your children, you may wish to talk with your citizen spouse about deferring your divorce until after you have obtained an immigration waiver. An immigration waiver is a commitment from the U.S. government that your past as someone who illegally entered the United States will now be overlooked and you will be permitted to legally enter and live in the United States. A change in the immigration rules, effective in 2012, with regard to illegal immigrant spouses of citizens appears to make the process of getting a waiver easier and shorter than it was previously.
If you feel your divorce cannot be delayed, you may consider contacting the American Immigration Lawyers Association about hiring an immigration lawyer and investigating other complex legal options that might give you post-divorce legal residency or get a potential post-divorce deportation suspended or cancelled.