My mom and my dh's mom know about our struggle with IF. We decided to tell them before my DH had surgery last March. I don't think his mother would have every forgiven me if he had surgery without her knowing! It is nice to be able to call my mom and vent when I'm feeling bad about everything. She doesn't really understand because she never had to try to conceive, but she can still comfort me.
My DH told one of his closest friends and I have told one of mine. Both of our friends are also going through IF.