I felt the same way when I started coming out to family as childfree, which became an amazingly complicated ordeal with family that I wasn't prepared for. We haven't even told my in-laws that we're never planning children; the bulk of the judgment comes from the fact that we don't have them YET (and we're only 32/33!) I never considered being childless by choice to be a controversial "lifestyle" choice until I started telling people about it. Especially since I don't really feel this is a choice; it's how I'm wired and the only choice involved is choosing not to push myself into something because that's "normal". It's hard as hell.
I cannot even imagine what my in-laws would say if they found out I wasn't monogamous with my husband. Because of that, I don't see myself ever being open with family about this, and that makes me sad. Already I want to tell my mom, who I'm pretty close with, about my boyfriend, but I know she'd never ever ever ever understand, so she looks at me confused when I say things like "I'm spending the weekend with my best friend's boyfriend", so even that much information is hard to share.
Good luck to you as you go through this so openly!! It takes a lot of courage, and that's such a shame.