Hope you don't mind me stepping in...
In my pov (and it's just that - a pov) sometimes, when people say "real" in relation to a parent, I don't think the implication is that the other is "fake"...the implication seems to take on the form that the other is "less than".
And that's why I don't consider my kids' firstmoms as their real moms - because I'm not "less than". And that's why I don't consider myself my kids' real mom - because their firstmoms aren't "less than".
There's room for everyone in this equation, ya know?