15 Lessons Movies Can Teach Us About Cheating

Lesson: Beware the rationalization that it's "meaningless sex."

Diana (Demi Moore) and David (Woody Harrelson) are a happily married couple in desperate need of cash. When a rich, handsome man with a great head of hair (Robert Redford) offers them $1 million for one night with Diana, they tell themselves it's OK because the sex won't mean anything. But even after the deed is done, David's jealousy continues to eat away at him and the marriage.

Lesson: Cheating offers a confusing combination of guilt and giddiness.

Sammy (Laura Linney) is a single mom who doesn't particularly like her boss, Brian (Matthew Broderick), so their sudden love affair takes her by surprise; she can't believe how much fun it is. One particularly poignant scene shows her driving home after a tryst with Brian, grinning like a school girl then slipping into "what have I done?" mode in a matter of seconds.

Lesson: Affairs can upend your life in ways you won't predict.

This drama captures one of the scariest parts of falling in love: when you aren't sure if the object of your affection reciprocates your feelings. When it's finally obvious that Carol (Cate Blanchett) and Therese's (Rooney Mara) relationship is something more, Carol decides to leave her husband — who later argues that her same-sex relationship makes her unfit to be a mother.

Lesson: Affairs can lead to long-term love.

Rarely, an affair can bring two people together for the long term, as is the case with Johnny Cash (Joaquin Phoenix) and June Carter Cash (Reese Witherspoon), who start as lovers but remain married for the rest of their lives. The key is how you handle the situation: before Johnny and June inflict too much harm on their families, they realize they both need to stop screwing around and commit to each other.

Lesson: Be very, very careful who you sleep with.

This movie doesn't glorify or endorse cheating. Instead, Fatal Attraction positions infidelity as something you later regret and just want to get past. Which is possible, unless the person you cheat with starts stalking you and exacting scary, scary revenge, which is exactly what happens to Dan (Michael Douglas) after his one-night stand with Alex (Glenn Close).

Lesson: Having an affair might mean you need a change in life.

Pearl (Diane Lane) loves her husband and her family, but because she got pregnant and married as a teenager, she feels like she missed out on life. Her affair with "the blouse man" Walker Jerome (Viggo Mortensen, at peak hotness) allows her to imagine a completely different life for herself. But when Walker sees her with her family, they both realize it's just a fantasy. "I can't go to California with you," Pearl tells him. He replies simply: "I saw."

Lesson: Your spouse knows when something's up.

We can't really blame Connie (Diane Lane, again) for cheating on her husband and banging Paul (Olivier Martinez). But her husband (Richard Gere) can definitely tell she's acting strange and hires someone to follow her, and things just get worse from there. Which leads to another lesson: do not underestimate the rage that cheating can inspire in the jilted spouse.

Lesson: Lust fueled by propinquity is real.

Humans often develop affection for the people they spend a lot of time with. In high school, it's a guy in your math class. In college, the girl in your dorm. The grown-up version of that plays out in extramarital affairs that start in the office. In the case of Flipper (Wesley Snipes) and Angie (Annabella Sciorra), there's the added allure of sleeping with someone entirely outside of their usual social circles and cultural backgrounds.

Lesson: When you're dissatisfied with your marriage, cheating becomes a coping mechanism.

Brad (Patrick Wilson, at maximum hotness) and Kate (Kate Winslet) feel unfulfilled by their spouses for different reasons. So when they strike up an affair that takes place during playdates, they spend a lot of time fantasizing about the future they could have together. But really, their relationship is just an escape from their marital problems.

The Lesson: Even when someone's life appears flawless, you never know what's going on behind the scenes.

In this incredibly complicated web of romantic intrigue, all four characters project the appearance of cool, successful people in happy relationships. But beneath the surface, they are all a total mess, never quite satisfied with what they have.

Lesson: Affairs can be intensified by a shared traumatic experience.

The affair between Maurice (Ralph Fiennes) and Sarah (Julianne Moore) unfolds against the backdrop of World War II-era England, and couple's steamy and romatic sex feels weightier with the sound of air-raid sirens in the background. The way the affair ends only makes it that more melodramatic.

Lesson: Clandestine sex can be super hot.

Like The End of the Affair (also starring Ralph Fiennes, also at peak hotness), this story plays out against a wartime background, which makes the trysts between Laszlo (Fiennes) and Katharine (Kristin Scott Thomas) super intense. What's more relatable is how the pair's encounters capture the passion of being in a new relationship — that phase when you just can't get enough of each other. The fact that their new-relationship phase is totally secret adds to the intensity.

Lesson: Beware of serial cheaters.

I don't necessarily believe that "once a cheater, always a cheater," but it's also foolish to assume there is only one other woman. The comedy The Other Woman is fairly ridiculous, but I do love the way that Carly (Cameron Diaz), Amber (Kate Upton), and Kate (Leslie Mann) band together to plot revenge on the man deserving of their ire, rather than lash out at each other.

Lesson: Affairs often involve lying and denial.

This depressing drama starts with Jack (Mark Ruffalo) and Edith (Naomi Watts) cheating on their spouses, who in turn start cheating on them with each other. Both "couples" weave a web of lies even as everyone starts to have a pretty good idea of what's going on. The compromised morals on everyone's part add to the bleak hopelessness.

Lesson: Infidelity and parenting don't mix.

Balancing a marriage and a sidepiece requires a lot of time and energy. Something is bound to fall through the cracks. As the affair between Ben (Kevin Kline) and his neighbor (Sigourney Weaver) unfolds, we see their kids left alone to make terrible and often disastrous decisions.