When filing Form I-751, Petition to Remove Conditions on Residence, you must submit documentary evidence that your marriage was concluded in good faith. Even if you are not filing with your spouse and applying for a waiver of the joint filing requirement, you should still submit as much proof as possible to show that you have/had a good faith and genuine marriage (and not a fake or fraudulent alliance concluded just to receive US citizenship).
The following evidences, if applicable, should be sent to USCIS to prove that you and your spouse have a good faith marriage:
– Children. Copies of birth certificates of your joint children or records of jointly adopted children.
– Shared finance. Various copies of jointly filed tax returns, bills regarding large purchases, joint savings and bank accounts, loan statements, copy of your mortgage or deed for your family home. If you are not leaving together with the spouse there must be a good explanation as to why.
– Insurance documents. Joint automobile and home insurance policies, life insurance policies that list you or your spouse as the beneficiary in case the other dies.
– Estate documents. Copies of your estate documents such as wills, trusts, etc.
– Time together. Photographs of you two as a happy couple, copies of travel documents for a honeymoon or a family vacation. You can also provide information that you and your spouse are members of the same clubs, organizations, teams, and other associations.
– Affidavits and correspondence. This is not the strongest evidence, however, you can additionally submit letters, emails, social media posts that you and your spouse sent to each other during your relationship. You can also submit a personal statement describing how you two met and details of your relationship. Letters, emails and affidavits from other people that address you as a couple also may be used as a proof of a bona fide marriage.
Generally, any documents containing both of your names will serve as an evidence of a good-faith marriage. The more documents you can provide the better.