The femme fatale is more glamorous, but she's not the only feminine archetype in the world of film noir. The other side of the femme fatale is her opposite number, the “good woman” who just can't help but love the doomed protagonist.

Some have described this in terms of the classic and highly destructive “virgin/whore” dichotomy imposed on women in many societies. This is surely accurate, but the good woman of noir is not always defined as a pure or naïve virgin. That isn't really her main role. Instead, she's a symbol of what the noir protagonist can never achieve, because in his heart of hearts he's just not that type of guy. Stability and family love, tranquility and peace- all of the things that the far majority of human beings actually crave.

The noir hero craves them too, but in the end he can never quite bring himself to commit to them. He's a loner by nature, and he doesn't spend all that time on the dark side of the street on a lark. It's his natural habitat; it's where he belongs. That's why- as in Robert Mitchum's character in “Out of the Past”- he will always be drawn back to the femme fatale. She represents his fate and his eventual destruction, because she's much closer to his own essential nature.

The good woman of noir has love to offer him, but he cannot take it. The femme fatale offers nothing, but inside himself he knows he's doomed and always has been. So it's the femme fatale he'll eventually choose, leading inevitably to his own demise. His uncontrollable attraction to the femme fatale is nothing more or less than a suicidal compulsion. It's all just part of the fundamental pessimism of film noir.