I think the branding was enough to keep men from giving them a second look, much less lusting after them. I need to re-watch the episode, but I got the impression that all their breeding was a result of rape.
I don't think they were like the Musai - irresistible to men; they're just beautiful women who act unattainable and are, therefore, more of a challenge to some men.
I'm sure you're right that it's going to get ugly when Juliette learns Adalind is having Nick's baby.
