Can't invite my female partner? Really?

Christina • A half dozen in the house!
I tried to invite my wife today (since she is my partner & I'm pregnant with her baby). When I entered her name and email, I got a pop-up saying I can't add a mom as a partner. Wth? Can someone fix this hurtful and offensive message please? I figured that since there's a same-sex group, Glow didn't discriminate against gays. Guess I was wrong. :(