katya-her secret??

watching the movie i assumed katya was bisexual or a lesbian. she seemed to use men, but have a genuine connection with her female costar. it seemed obvious, was it suppose to be obvious to pierre, but he couldn't see it because he was so attracted to her? i thought that was a major theme. pierre told her his darkest secret, yet she never told him hers. she just played him. am i right?? other thoughts??