Though it is more difficult to obtain, I would suggest going after the Declaration of Validity. You may eve be able to move forward on both issues at the same time. I've provided a link to the forms required. You do need to consult with a local attorney.
To sign a declaration of invalidity of marriage, the court must find "(i) The marriage or domestic partnership should not have been contracted because of age of one or both of the parties, lack of required parental or court approval, a prior undissolved marriage of one or both of the parties, a prior domestic partnership of one or both parties that has not been terminated or dissolved, reasons of consanguinity, or because a party lacked capacity to consent to the marriage or domestic partnership, either because of mental incapacity or because of the influence of alcohol or other incapacitating substances, or because a party was induced to enter into the marriage or domestic partnership by force or duress, or by fraud involving the essentials of marriage or domestic partnership, and that the parties have not ratified their marriage or domestic partnership by voluntarily cohabiting after attaining the age of consent, or after attaining capacity to consent, or after cessation of the force or duress or discovery of the fraud, shall declare the marriage or domestic partnership invalid as of the date it was purportedly contracted;"
I do not see fraud in this situation. You knew why you were getting married.
Besides the family law issues, you have a problem with the immigration authorities. You just admitted to committing marriage fraud. Both you and the other person can be imprisoned by the federal government and fined upon being convicted.
To obtain a declaration of invalidity in WA, the petitioner must prove a statutory basis. I doubt that you should go to court and testify that you committed fraud.
To obtain a decree of dissolution of marriage in WA, one or both spouses just need to allege that the marriage is irretrievably broken. Nothing must be proven about whose fault the marriage is broken.
You should review the specific facts with your attorney to find out your legal options.