Spoilers ahead.

I’m extremely happy with her, and part of it has to do with the fact that she is at once completely familiar to me, so that I can be myself and she knows me very well and I trust her completely, but at the same time she is also a complete mystery to me in some ways. And there are times when we are lying in bed and I look over and sort of have a start. Because I realize here is this other person who is separate and different and has different memories and backgrounds and thoughts and feelings. It’s that tension between familiarity and mystery that makes for something strong, because, even as you build a life of trust and comfort and mutual support, you retain some sense of surprise or wonder about the other person.

—Barack Obama, discussing his marriage to Michelle, 1996

Romance, to be unromantic about it, is a matter of information gained over time. Dating, to be slightly more romantic about it, is a matter of ongoing discovery. Over the days and weeks and months, the black-and-white contours of initial attraction—he's funny, she's pretty, they're both ENFJ—get colored in, and the little things that will become the everything—the likes, the dislikes, the thoughts about the word "slacks"—take on their shades. If months become years, sure, the hair may become a little thinner, the thighs a little thicker, the E a little more I. But if you keep liking what you find in that other person, the idea goes—if the good discoveries, over time, keep outweighing the bad—you move forward, together. You meet friends. They become your friends. You meet family. They become your family. You keep learning. You keep filling in the blanks.

Marriage is, on top of everything else, two people saying they want to keep discovering each other, over time.

Which makes it, on top of everything else, an enormous leap of faith. People are unpredictable. They are also changeable. And that tension—familiarity and mystery, bound together—helps explain the profound creepiness of Gone Girl, one of the most profoundly creepy feature films of recent memory. Many of the reviews of the movie, on the occasion of its premiere this weekend, have called the film misogynist or feminist or both at the same time. But while you can read David Fincher's latest film as a kind of third-wave-riding Rashomon—and while, yes, any movie about a person who is both female and murderous will always, on some level, invoke the vagina dentataGone Girl isn't just a consideration of man-versus-woman. It's also a consideration of man and woman. A consideration of partner and partner, over time. Gone Girl is more, and maybe most, interesting as a look at what happens when the Kierkegaardian element of marriage—that leap of faith into another person—ends up going terribly, terribly wrong.

* * *

This particular marriage unfolds in a vaguely anonymous McMansion in a vaguely anonymous suburbia, and the anyplace-ness of both, we are meant to understand, offers its own kind of spectral menace. Nick and Amy Dunne, both New York-based writers before they were laid off in the recession of 2009, are extremely aware of themselves as makers of—and participants in—a culture dominated by image and expectation. To them, romantic partnership—its meet-cutes, its stay-cutes—is its own kind of media event. Nick and Amy talk a lot about "other couples" and "most people," and they congratulate themselves on how charmingly non-basic their own coupledom manages to be. "Don’t land me in one of those relationships," Amy says in Gillian Flynn's book, "where we’re always pecking at each other, disguising insults as jokes, rolling our eyes and ‘playfully’ scrapping in front of our friends, hoping to lure them to our side of an argument they could not care less about. Those awful if only relationships: This marriage would be great if only… and you sense the if only list is a lot longer than either of them realizes."

If only, you know, Amy weren't on her way to becoming a murderer. If only Nick weren't on his way to becoming a liar. The Dunnes were never, under any definition of the term, good people. But the ongoing twist of a twist-filled movie is that they become, together, grotesquely terrible people. And their terribleness, at least the parts of it Fincher allows us to see, is contingent and contextual: Nick and Amy have, by virtue of their marriage itself, helped to make each other who—and what—they are. Mars and Venus, in Marriage.

“Men always say that as the defining compliment, don’t they?" Amy says, famously, in the novel:

She’s a cool girl. Being the Cool Girl means I am a hot, brilliant, funny woman who adores football, poker, dirty jokes, and burping, who plays video games, drinks cheap beer, loves threesomes and anal sex, and jams hot dogs and hamburgers into her mouth like she’s hosting the world’s biggest culinary gang bang while somehow maintaining a size 2, because Cool Girls are above all hot. Hot and understanding. Cool Girls never get angry; they only smile in a chagrined, loving manner and let their men do whatever they want. Go ahead, shit on me, I don’t mind, I’m the Cool Girl.

Is that a record of Mrs. Dunne's daily thoughts, or a performance of those thoughts? How much of her—she of the model-gorgeous good looks, the Ivy League education, the childhood spent as the subject of the book series Amazing Amy—has been shaped by others' expectations? Where does idealized Amy end, and real Amy begin? We are never sure. She herself, maybe, is never sure. And this is part of the point. In Gone Girl's moral universe, expectation begets evolution. And then evolution begets expectation. Person and idea-of-person become extremely difficult to disentangle.

That core ambiguity—who is at fault for Amy being Amy, and doing what Amy does?—carries Gone Girl out of the realm of gender politics and into the realm of relationships writ cosmic. Soon after Nick and Amy marry, a series of strains—the lost jobs, a move to suburbia to care for a sick mother, the death of that mother, a disagreement about whether to have children—cause Amy to lose whatever Cool she once possessed. There was very little Nick could do about that, just as there was very little Amy could do about the affair Nick began with his young student. The inflection points in that transformation are difficult to discern. Had she ever been the person he thought she was? Had he been the person she'd forever-ed? Does it matter?

"For better or for worse" would suggest that it does not. Yes, the information the two had gathered about each other during their days of dating and learning and deciding had, in the end, proven misleading. Yes, it had been nullified, ultimately, by the series of known unknowns that we shorthand under the rubric of "life." But: "for richer, for poorer." "'Til death do us part."

These are tensions that take a film full of murder and melodrama and make it, in the best sense, mundane. They are also the things that elevate Gone Girl from taut psychodrama to full-on horror movie, because they suggest that the source of marriage's romance can also, in extreme cases, become a source of fear: You never really know, fully, the person you marry. And regardless, the person you marry—"life" and all that—will turn into someone different, over time. Whether it comes from John Donne or from Amy Dunne, the idea is the same: We are all, inevitably, products of each other. Friends and colleagues and—maybe most of all—partners are sources not just of companionship, but of influence. The people we choose help, in ways big and small, to make us who we are. We can only hope we choose well.

Amy and Nick did not choose well. The extreme outcome of that misfortune is manipulation and murder. But the less extreme outcome, in Fincher's telling of their story, is a kind of questioning nihilism. What does marriage—for better, for worse—do to us? If "he said" and "she said" dissolve into "they said," what becomes of the individuals doing the telling? Where does husband end, and wife begin? And what do you do when the person you're married to becomes, inevitably, different from the person you married?

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