If you intentionally entered into the marriage solely for the purpose of providing your roommate with immigration status in United States , you would be theoretically subject to a claim of fraud , but it would be hard for the prosecutor to prove that you had intent to defraud.
In order to get an annulment you will have to prove fraud and it appears that you were complicit in this agreement to marry in order to provide immigration status to your roommate. So you were not defrauded or deceived.
You can , however , get a divorce . if you can prove one of the grounds acceptable in New York State for divorce or both of you are agreeable on one of the grounds.
If you are living in the New York City metropolitan area, I strongly suggest that you call me at 212-370-1660 to discuss arranging for a meeting to discuss mediating your divorce which will be faster and cheaper and a lot less emotionally straining.
Leonard M. Weiner, Esq./Divorce Solutions