Most of my friends know (most of my close friends are poly anyway...) and most of my family knows. Results have been varied. My brother and step-dad don't understand it, don't want to talk about it. But they still love me
My mum and sisters are happy to hear about my partners and have all met my boyfriend, though not my girlfriend as she hasn't been to England since we got together. They don't necessarily understand it, but are of the opinion that as long as we're not hurting anyone and are being careful about the child, all is good.
Though it's taken us a long while to get here. When my mum first found out, she said she didn't want to hear about it, or about how fine bf's wife (now my gf) was with it. That was about a year ago now. I've been...lucky, I think.