Nina’s role as Victor’s romantic interest is as tough to characterize as, well, everything else in this complex short story. Does he really love her? We’re not sure. Does she love him back? We can be pretty sure that one’s a no, but even in that case, how does Nina feel about Victor? Is he really just another disposable lover she happens to meet time and time again? The point is, the label "Romantic Interest" is about as specific as we can get with any certainty. The rest is up to interpretation.