Even ‘Good’ Lies Take Toll on Relationships, New Study Finds

Most people likely think of themselves as honest partners. Yet when researchers asked 656 adults to describe a time they were dishonest with someone they loved, almost everyone had a story ready, and those stories were often painful even when the lie was meant to protect the other person.

A new study from the University of Copenhagen, published in Personal Relationships, set out to map dishonesty in romantic relationships: what forms it takes, what topics it covers, why people do it, and what happens afterward. Lying, hiding information, and cheating rarely stayed contained, according to participants’ accounts. Many people described dishonesty as something that wore down trust, shut off communication, and left a relationship damaged.

Here is the part that surprised the researchers: it barely mattered whether someone lied to protect themselves or to spare a partner’s feelings. In people’s own accounts, the damage to the relationship looked about the same either way. Good intentions did not appear to cancel out a bad result.

How People Lie in Romantic Relationships

Researchers recruited a U.S.-based sample of 656 adults through the survey platform Prolific and asked each person to describe, in their own words, a dishonest act involving a romantic partner. Most were currently in a relationship of at least four months. Others had been in one at some point, and a small group had never had a relationship that long and were asked what they might hide from a future partner. Everyone wrote a detailed account, at least 200 words about the incident and 100 more about what came of it. Participants ranged in age from 18 to 83, and most identified as heterosexual.

From those hundreds of accounts, the team sorted dishonesty into four forms. First is outright lying, from small white lies, like praising a partner’s cooking when it fell flat, to serious ones, like denying an affair when asked directly. Second is withholding information, which is not technically lying but covers keeping secrets or staying quiet about something a partner would want to know. Third is deception through behavior rather than words, such as deleting text messages, hiding objects, or acting perfectly normal to cover up something that is not. One person described keeping up “a façade of normalcy.” Fourth is infidelity, defined broadly to include emotional affairs and online behavior like sexting, not only physical cheating.

Eight Things People Lie About

Beyond how people deceive, the researchers cataloged what they deceive about, and eight topics emerged: emotions, self-image and personal history, physical and mental health, sexuality, money, whereabouts, social relationships, and wrongdoing.

Money came up often. Participants described hiding spending, lying about income, and keeping secret bank accounts. One man admitted to being dishonest “on numerous occasions” about how much he brought home each payday.

Sex was another common area. People lied about their history, their desires, and their satisfaction. One woman said she regularly faked orgasms, explaining that she “felt a pressure to pretend” and lacked “the energy to fight.”

Health showed up too. One man had hidden a serious kidney condition from his wife, worried that her family would not have approved of the relationship had they known.

How One Lie Snowballs in Relationships

In many accounts, dishonesty bred more of itself. People who lied started to suspect their partners were lying back. Others had to keep inventing cover stories to prop up the original lie, always having to stay, as one person put it, “on your toes.”

Researchers named one pattern “The Slowburn.” A rush of excitement or relief right after the lie slowly curdled into guilt, shame, and regret that built over weeks and months, weighing on both the person and the relationship.

Getting caught was not required for the fallout. Even when a lie went unnoticed, people still reported feeling guilty, pulling away, and growing suspicious of their partner in return. One participant put it simply: “Trust is like the glue that holds a relationship together.” Once that glue weakens, whether from a lie that surfaced or a secret kept quiet, rebuilding it can take a long time.

When Lying Led to Honest Conversations

Not every story ended badly. A few participants described a lie as an unexpected turning point, a pattern the researchers called “The Repaired Bond.” Being found out forced conversations they had been dodging, and some said their relationship came out stronger. One reported “positive results over the years”; another said it “made the relationship stronger.” Only a small number of participants described this kind of outcome. For most people, dishonesty led to broken trust, distance, drawn-out arguments, and often a breakup.

Underneath it all, the study points to two basic motives. Self-protective lying is what it sounds like: hiding something to avoid consequences for oneself, whether conflict, embarrassment, or rejection. Partner-protective lying is trickier. These are lies people tell themselves are for the other person’s benefit, like concealing money trouble so a partner will not worry.

Researchers deliberately labeled the second kind “alleged” partner-protection, because only the liar knows whether shielding a partner was the real reason or simply a more comfortable story to tell. Either way, the motive did not change the result. Selfish or well-meaning, both kinds of lying tended to leave similar wreckage. As one participant reflected, hiding hard truths risks “creating a false sense of security that erodes trust over time.”

People say they prize honesty in love. What these accounts show is that they live up to it less consistently than they’d like to think, and the gap between the relationship they think they have and the one they actually have may be the quietest kind of harm.

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