Hi,
Like other members here have said, try sending as much proof as you can. What I suggest is, since hindi kayo masyado ma-picture, you can write a love story about you and your husband. Magkwento ka. Since walang pictures, daanin mo na lang sa story. Isulat mo pano kayo nagkakilala, kelan mo sya sinagot, first kiss, saan-saan kayo pumunta, first anniversary celebration, etc. Kaw na bahala. My wife made a 6-page story about our entire relationship from beginning till now. Also, i-explain mo din sa letter na hindi kayo ma-picture kaya walang masyadong picture kayong dalawa.
Of course, isama mo rin yung mga emails, chat logs, phone bills, love letters/greeting cards to each other at kung anu-ano pang proof about your relationship that you think will benefit you.
Hope this helps and good luck!