Utility bills need to be under both names, but if some are in your name and some in her name, submit those. They show you are living there if some are in your name.
Yes, send the care statements, it shows you are living there.
Submit the auto insurance papers again.
Send copies of what photos you have.
Do you ever see her grown children? Do they have children and do you give presents to the grandchildren? Do her grown children know about you? Have them give affidavits, too.
Start to save all junk mail and send the envelopes w/ your names on them, too.
Get the job letters.
How about church? Do you go to church?
What about her co-workers and yours. Can they write affidavits that you talk about her at work and she talks about you to her co-workers at work?