"Life is short. Have an affair."

That's the infamous tagline of the website Ashley Madison, a dating and relationship site for married people looking to cheat.

The sordid story of Ashley Madison is back into the spotlight thanks to a new Netflix docuseries, "Ashley Madison: Sex, Lies & Scandal," out Wednesday. The three-episode show explores the beginnings of Ashley Madison in 2001, its rise in popularity and its bombshell 2015 data breach that revealed the information of over 30 million users. Ashley Madison continues to operate to this day with "more than 80 million sign-ups since 2002 and hundreds of thousands of new Members monthly," per its website.

Netflix's series features interviews with people who explain why they decided to join Ashley Madison. Sam Nader, a Christian YouTuber named in the Ashley Madison hack, candidly describes how he found life boring not long after marrying his wife. An advertisement for Ashley Madison bearing its notorious slogan intrigued him.

So why do people cheat? It's a complicated, difficult question − and one that's undoubtedly been on the minds of anyone who has ever been betrayed this way by a partner. Though affairs often get chalked up to a miserable partner escaping a troubled, toxic relationship, the truth is that infidelity occurs even in healthy, stable marriages.

"An affair is always an escape from something, even if it's not necessarily the marriage itself," licensed psychotherapist Kevin Barry previously told USA TODAY. "People often do it to relieve some internal stress, like, 'My marriage is great, but I need something else.' So they find relief through someone else, where everything seems perfect because you're not dealing with the stressors of a committed marriage."

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What is 'affair fog' and why does it matter?

A 2020 study found that in addition to relationship woes, affairs are motivated by low self-esteem, stress and boredom. Those findings were in line with past research that revealed people overwhelmed with stress were more likely to cheat as an emotional regulation strategy.

What also might be at play is a phenomenon experts call "affair fog." This occurs when the person engaging in an affair is hyper-focused on the excitement of a new relationship and not considering the gravity of what they're doing.

"Someone in the affair fog will be immersed in this fantasized honeymoon phase of the new fling, and they don't think about the emotional toll it takes on the people around them," relationship coach Darlene Kollet previously told USA TODAY.

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Affairs are a temporary thrill − and put your partner in 'complete crisis'

Some people may end up leaving their spouse for the affair partner. But experts say that more often than not, the adrenaline rush of an affair provides only a temporary thrill – with permanent consequences.

"The fog clouds your judgment and makes you try to justify the affair by finding excuses to pick your marriage apart," Barry previously told USA TODAY. "But once the fog begins to lift, you start to realize: 'What have I done?' 'My family isn't actually that bad. My kids are going to hate me.' 'How do I go back?'"

The person being cheated on is also "put in a complete crisis" because of their partner's decisions, Kollet previously told USA TODAY. Narcissists, who lack empathy for others, including their partners, are also more likely to cheat, experts explained.

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Affairs often come with self-doubt for the person who's cheated on.

"They're doubting their reality, like. 'How was I not enough? What did I miss?' And this results in lower self-esteem and a feeling of helplessness," Kollet previously told USA TODAY, adding it's better to cope with stress or unmet needs in a relationship with effective communication than with deception.

"It comes down to letting your spouse know how you feel," she said. "Confront your partner about how you feel or what you're unsatisfied with. Affairs have a lot to do with internal struggles, so figure out where these triggers are really coming from."

Contributing: Jenna Ryu and Mary Walrath-Holdridge, USA TODAY