How can you send a Christmas card to a friend without their address?

This is a dear person to me, since we both left Answerbag. She made the switch to Fluther with me two years ago. We PM each other at least every other day. She knows all about yours truly, from Facebook, but she will not tell me anything about herself. I understand and respect her privacy, but if she cannot trust ol’ John, then she cannot trust a sole on this earth. Am I asking to much from her for the last two years of our friendship? I just wanted to mail her a Christmas card and nothing more. Question: am I wrong here? If so, why?