Female character, Lapis, and the Batman films take severely failing grades on Bechdel, so it's almost a given that female character = love interest for Batman.
Heh - true, but a girl can hope that Nolan, who has done so well by the franchise, might actually overcome this as well.
That said, I've never felt Catwoman has to be a romantic interest for Batman. In a Nolan film she can work as a counterpoint to his viewpoint in much the way the male villains Ra's and the Joker did for the last two films, and they did that without any noticeable sexual frission (alternative readings aside.)
Her stories are ever so much more interesting when she's not interested in Batman romantically. A truly interesting twist would be to have him enamoured of her, and her completely uninterested in him. Not that they'd ever do such a thing.