Eiredpf is right also chect the list below, the more you give is better.
1. Documentation showing joint ownership or property; or
2. A lease showing joint tenancy of a common residence; or
3. Documentation showing co-mingling of financial resources; or
4. Birth certificate(s) of child(ren) born to you, the petitioner, and your spouse together; or
5. Affidavits sworn to or affirmed by third parties having personal knowledge of the bonafides of the marital relationship (Each affidavit must contain the full name and address, date and place of birth of the person making the affidavit, his or her relationship to the petitioner of beneficiary, if any, and complete information and details explaining how the person acquired his or her knowledge of your marriage); or
6. Any other relevant documentation to establish that there is an ongoing marital union.