Cheating: it’s the ultimate relationship violation and a notorious relationship killer. A favorite gossiping pastime, the phenomenon is frequently discussed but difficult to study. The goal is to avoid getting caught, so why confess infidelity in the name of science?

But scientists can offer us new insight on a topic often shrouded in stigma and mystery. As researchers have recently demonstrated, cheating is rarely a simple affair. There are many reasons why people cheat, and the patterns are more complex than common stereotypes suggest. A fascinating new study sheds some light on these motivations.

The investigation included 495 people (87.9 percent of whom identified as heterosexual), who were recruited through a participant pool at a large U.S. university and through Reddit message boards with relationship themes. The participants admitted to cheating in their relationship and answered the question at the root of the mystery: Why did you do it? An analysis revealed eight key reasons: anger, self-esteem, lack of love, low commitment, need for variety, neglect, sexual desire, and situation or circumstance. These motivations not only influenced why people cheated but how long they did so, their sexual enjoyment, their emotional investment in the affair and whether their primary relationship ended as a result.

Though most cheating involves sex, it is rarely just about sex itself. Most participants felt some form of emotional attachment to their affair partner, but it was significantly more common in those who reported suffering from neglect or lack of love in their primary relationship. Around two thirds of participants (62.8 percent) admitted to expressing affection toward their new partner. And about the same proportion (61.2 percent) engaged in sexually explicit dialogue with them. Roughly four out of 10 (37.6 percent) had intimate conversations, while one in 10 (11.1 percent) said, “I love you.” Those who reported feeling less connected to their primary partner experienced greater emotional intimacy in the affair, perhaps as a way of fulfilling that need. Similarly, when infidelity was linked to lack of love, individuals found the experience more intellectually and emotionally satisfying.

Participants’ satisfaction with sex differed depending on the reason for their affair. People reported feeling more sexually fulfilled when they cheated because of desire, lack of love or a need for variety. Those who cited a situation as the primary cause were far less satisfied. Much of the sexual activity was limited to kissing (86.7 percent) and cuddling (72.9 percent). In fact, the study found that only half of the cheaters reported having vaginal intercourse.

The reason for the infidelity also greatly impacted its length. In some cases, the relationship was a brief tryst, while others were a longer and deeper attachment. Those who cheated because of anger (such as a wish to “seek revenge”), lack of love or need for variety had a longer affair, while those motivated by the situation (such as those who were “drunk” or “overwhelmed” and “not thinking clearly”) ended it earlier. Women also had a longer affair on average than men.

In the end, only a third of participants ultimately admitted the cheating to their primary partner. Women were more inclined to fess up than men. Those who came clean were more likely to have cheated out of anger or neglect rather than sexual desire or variety. This suggests that their confession was possibly a form of retribution and a way to exact revenge instead of a way to clear their conscience. The participants who confessed were also more likely to form a committed relationship with the affair partner.

While infidelity is typically a clandestine enterprise, some cheaters were less careful than others, perhaps intentionally. Those cheating because of lack of love went on more public dates and displayed more public affection toward their partner. PDA was also common for those seeking variety or looking to boost their self-esteem. On the other hand, situational cheaters were less inclined to cheat out in the open, perhaps because they hoped to return to their primary relationship without getting caught.

So is an affair really a relationship killer? Ultimately, the fate of the participants’ primary relationship depended less on the act itself and more on what motivated it. Cheating was more likely to end a relationship when it arose from anger, lack of love, low commitment or neglect. And it was less likely to do so when the infidelity was circumstantial. Surprisingly, only one in five (20.4 percent) of relationships ended because of the affair. The same number of couples (21.8 percent) stayed together despite their primary partner finding out, while slightly more (28.3 percent) stayed together without their partner discovering their infidelity. The remaining relationships broke up for noncheating reasons.

Rarely did infidelity lead to a real relationship. Only one out of 10 of the affairs (11.1 percent) ultimately turned into a full-fledged commitment—one of the preconceptions that turns out to be true.