If you are applying for an immigrant visa or green card based on marriage to a U.S. citizen or permanent resident, one of your most important tasks is to prove that your marriage is the real thing, not just an arrangement to get you a U.S. green card (lawful permanent residence).
Naturally, you are most likely to succeed, and receive approval for a green card, if you can show a happy, traditional marriage. However, this does not mean that marital arguments or even living separately should lead the officer to deny your green card. If you have serious problems, be reasonably open about the cause and the detailed steps the two of you are taking to deal with them.
For example, you may be meeting with a marriage counselor or religious leader on a regular basis. That's good -- in fact, it may be among the strongest forms of evidence of a real, bona fide marriage. People trying to commit marriage fraud do not commit time and money to trying to work out issues in their marriage!
If, however, the consular or USCIS officer appears to wrongly believe that only happy marriages qualify you for a green card (which is not uncommon), ask to reschedule the interview so that you can consult with or bring a lawyer.
If you have actually received a legal separation (court ordered) or filed for divorce, however, your prospects for green card approval are dimmer. A legal separation or divorce filing will ultimately lead to a denial of your green card.
There is an exception if your U.S. citizen or permanent resident spouse is subjecting you to abuse (physical or emotional cruelty). In that case, divorce will not destroy your green card eligibility if you file what is called a self-petition on USCIS Form I-360. You must file this before the divorce decree becomes final, or within two years of the final decree if you can show that the divorce was connected to the abuse.
The self-petition declares that since you are being abused, your spouse can’t be counted on to assist you with the green card application process. You will be allowed you to start or continue the process on your own. You will need to submit documentation of the abuse, such as police or medical records, statements from friends, family, and others, records from shelters you have stayed in, reports by counselors, and so on.
Talk to your local battered women’s shelter or other nonprofit or charity organization; or see a lawyer if spousal violence is holding up your application.