Why do people have affairs? The psychology behind infidelity

Why do people have affairs, and what makes someone cross a boundary they once promised not to? Infidelity is rarely driven by one reason. From personal struggles and relationship dynamics to the pull of novelty and emotional connection, there can be far more going on beneath the surface than simply falling out of love.

When an affair comes to light, one question tends to dominate: why did they do it?

It’s tempting to look for a single explanation. Perhaps they had fallen out of love, weren’t happy in the relationship, or were attracted to someone else. But infidelity is rarely that straightforward.

“It’s a deeply human question, yet there is rarely a single, simple answer,” says Dr Steven Mahan-Taylor, consultant clinical psychologist at London Bridge Therapy.

In his experience, affairs can emerge from a combination of individual vulnerabilities, relationship dynamics and unmet emotional needs.

Understanding those reasons doesn’t excuse the decision to cheat. But it can help explain how someone reaches the point of crossing a boundary.

It’s not always because the relationship is unhappy

One of the biggest misconceptions about affairs is that they automatically mean a relationship was failing.

Relationship and sex therapist Georgina Vass says women, in particular, can be experiencing difficulties in their relationship while also dealing with something much more personal.

“Women tend to be more active in evaluating the quality of relationships, and may assert problems with the relationship, but that does not necessarily mean they are not also going through something as an individual.”

In other words, relationship dissatisfaction and personal dissatisfaction can exist at the same time. Someone might feel disconnected from their partner while also struggling with their identity, confidence, ageing, sexuality or sense of independence.

Sometimes it’s about what’s happening internally

Mahan-Taylor says some people seek an affair because they are struggling with “low self-esteem, a need for external validation, unresolved trauma, fear of emotional intimacy, or difficulty expressing emotional needs”.

In these situations, the affair can become a form of escape. “The affair becomes a way of escaping uncomfortable feelings rather than addressing them,” he says.

The attraction, then, isn’t necessarily just about the person on the other side of the affair. It can be about how that relationship makes someone feel about themselves.

The need to feel different

Long-term relationships change. The intensity of early romance can give way to routine, familiarity and shared responsibilities. For some people, that transition can be difficult.

“The intensity and novelty that characterise the early stages of love are replaced by familiarity, routine, and shared responsibilities,” says Mahan-Taylor.

A new connection can offer a temporary escape from that familiarity – and from the version of yourself you may feel you’ve become.

“For some people, particularly those who associate excitement with emotional fulfilment, the attention and intensity of a new connection can feel intoxicating.”

The attraction may therefore be less about finding a “better” partner and more about rediscovering a part of themselves they feel they’ve lost.

Why there is rarely one answer

Perhaps the biggest mistake we can make when trying to understand infidelity is looking for one cause. Vass describes it as “a constellation of motives”.

Someone may be unhappy in their relationship, craving excitement, struggling with self-esteem and feeling sexually dissatisfied – all at the same time.

Another person may be genuinely happy but still vulnerable to an unexpected opportunity or a powerful need for validation.

And someone else may already be emotionally preparing to leave.

The important distinction is between understanding why an affair happens, and excusing it.

“Choosing to have an affair is always an individual responsibility,” says Mahan-Taylor.

But if couples want to understand what happened, simply asking Who was to blame? may not tell the whole story. A more useful question, he suggests, is: “What was happening in each of our worlds that made this relationship vulnerable?”

That doesn’t erase the betrayal. But it can reveal the individual needs, relationship patterns and choices that brought the affair about – and, for couples who want to move forward, what needs to change.

Words: Anne Fletcher, Images: Shutterstock