Tell me, why do you expect people to provide pictures, just so you can decide if its a true event, or not?
I've chatted to people on here, told them I'm meeting someone, and they ask me to take pics for them? Why should I? I'm doing it for my enjoyment, not as their personal porn star! I don't need to prove anything, just like the OP doesn't need to prove anything. There could be hundreds of reasons why there aren't pictures, reading the post it seems like it's quite a big step for his wife, and maybe she wouldn't feel comfortable being photo'd doing it.
At least they're turning their fantasy into reality, they don't need to prove anything to anyone, least of all you!