A recent study indicates that the tendency to become emotionally and mentally preoccupied with someone outside of a romantic relationship is driven by a complex mix of personality traits and relationship dynamics. The research suggests that this type of infidelity is not just tied to dark or impulsive personality traits, but also to generally positive characteristics like emotional sensitivity. The findings were published in Psychological Reports.
Infidelity is a common issue in romantic relationships, often leading to emotional distress and couples therapy. Historically, people have defined infidelity through physical acts, but modern perspectives recognize that subtle psychological behaviors also play a major role in relationship disengagement. One such phenomenon is extradyadic infatuation. This term describes a state where a person maintains their primary relationship but becomes cognitively, emotionally, and motivationally preoccupied with someone else.
To better grasp why some people develop these alternative attractions, scientists look at individual personality differences and relationship quality. For instance, a 2019 systematic review found that a combination of personal background and relationship dynamics strongly influences whether someone engages in infidelity.
Personality traits are often categorized into broad frameworks to understand interpersonal behavior. The Dark Triad consists of Machiavellianism (a tendency toward manipulation and emotional detachment), narcissism (an inflated sense of importance), and psychopathy (impulsivity and a lack of empathy). On the other hand, the Light Triad focuses on prosocial human characteristics. Introduced in a 2019 study, the Light Triad framework includes Kantianism (treating people as ends rather than means), humanism (valuing the dignity of individuals), and faith in humanity (believing in human goodness).
Another relevant trait is sociosexuality, which describes a person’s willingness to engage in casual sex without emotional commitment. Research, such as a 2021 study of young adults, indicates that dark personality traits and an openness to casual sex frequently interact to influence how people pursue short-term romantic encounters. The authors of the new study aimed to see how this blend of dark traits, light traits, sociosexuality, and relationship satisfaction predicts the specific experience of extradyadic infatuation.
“What initially caught our attention was the idea that infidelity is not always as straightforward as we tend to think,” said study author Teodora-Elena Huțanu, a PhD student at the Faculty of Psychology and Education Sciences at Alexandru Ioan Cuza University of Iași in Romania. “Rather than viewing infidelity simply as a matter of ‘good’ versus ‘bad’ people, we wanted to explore a more nuanced picture that considers Dark and Light Triad personality traits, sociosexuality, and relationship quality.”
The research involved a sample of 303 Romanian adults. Participants were between 19 and 64 years old and were currently in a committed romantic relationship. A key requirement for participation was that respondents had to report liking or feeling attracted to someone they knew personally, other than their current partner. Most of the participants were women, and the majority were married or in long-term relationships.
The respondents completed several questionnaires. They answered items assessing their Dark Triad and Light Triad traits. They also completed measures of their sociosexuality, rating their attitudes, behaviors, and desires regarding uncommitted sex. Finally, participants rated their current relationship satisfaction and the intensity of their extradyadic infatuation, which included their thoughts, emotions, and desires regarding their outside attraction.
In their initial analysis, the scientists found that people scoring higher on any of the Light Triad traits tended to report less extradyadic infatuation. Those scoring higher on Dark Triad traits, sociosexuality, or who had lower relationship satisfaction tended to report higher levels of infatuation.
When the researchers analyzed all these factors together to see which ones independently predicted extradyadic infatuation, a more complicated picture emerged. High psychopathy, high sociosexuality, and low relationship satisfaction reliably predicted greater preoccupation with an outside person. A lack of faith in humanity also predicted higher infatuation, suggesting that people with cynical views about others might invest less in their primary relationship and look elsewhere.
Interestingly, two traits behaved differently than expected once other variables were accounted for. Humanism, which initially seemed protective, became a positive predictor of infatuation. The researchers suggest that the emotional sensitivity and openness characteristic of humanism might make people more receptive to forming deep, emotionally meaningful connections with alternative partners.
In contrast, Machiavellianism became a negative predictor in the final analysis. Because extradyadic infatuation requires sustained emotional and cognitive energy, people high in Machiavellianism might avoid such intense attachments due to their preference for strategic, detached interactions. Narcissism and Kantianism did not emerge as statistically significant predictors in the final model.
“What surprised us most was that, even when looking at extradyadic infatuation as a more cognitive, emotional, and motivational form of infidelity, rather than simply as a behavioral transgression, some less adaptive psychological characteristics still remained relevant,” Huțanu explained. “At the same time, the unexpected changes in direction for Machiavellianism and Humanism were also particularly informative.”
“Our findings showed that both Dark and Light Triad traits contributed to its prediction, but in different directions,” Huțanu noted. “This is particularly interesting because it suggests that extradyadic infatuation cannot simply be understood as the result of being manipulative, impulsive, or otherwise ‘dark’.”
“Some of the characteristics involved may also reflect greater emotional receptivity and openness to meaningful interpersonal connections,” she added. “So, rather than asking whether someone who experiences extradyadic infatuation is simply a ‘good’ or ‘bad’ person, we may need to look at what kind of psychological and relational processes are making another person emotionally salient in the first place.”
The study has a few limitations to consider. The sample consisted mostly of women, which might restrict how well the results apply to men. Additionally, the researchers did not account for different relationship agreements, such as whether participants were in strictly monogamous partnerships or consensually non-monogamous arrangements. Open relationship structures might alter how traits like sociosexuality interact with relationship satisfaction.
“An important caveat is that we assessed extradyadic infatuation rather than actual infidelity behavior; therefore, we cannot determine whether participants acted sexually or otherwise on their attraction to an extradyadic person,” Huțanu said. “In addition, extradyadic infatuation may partly reflect an idealized or imagined representation of the other person, particularly when the actual interpersonal bond is limited.”
Because the data was collected at a single point in time, the findings cannot determine whether these personality traits cause infatuation, or if they simply tend to co-occur. “In my future research I would like to clarify how these cognitions and emotions unfold over time and whether extradyadic infatuation ultimately translates into behavioral infidelity or sustained extradyadic relationships,” Huțanu explained. “I am quite confident that this research is only the beginning of a broader effort to highlight more nuanced and comprehensive perspectives on infidelity, which may be psychologically more complex than its behavioral expression suggests.”
The study, “Personality, Relationship Quality, and Infidelity: Extradyadic Infatuation as Predicted by Dark and Light Triad Traits, Sociosexuality and Relationship Satisfaction,” was authored by Teodora-Elena Huțanu and Andrei Corneliu Holman.