Infidelity is that big blue shadow that tugs at relationship cords, whether or not it has already happened.

We say the word “cheating” because affairs are much like cheating the system—the universal system of love and respect and trust.

In the generic sense of the term, cheaters try to get the best of all worlds without putting in the effort of passing GO and collecting $200. They are hungry, and some of them may not even know it.

But cheating in a relationship isn’t exactly like sneaking a look at your smart peer’s answers on an exam. It’s not just about getting an A or extra Monopoly properties.

Infidelity is far more complicated. It is an arena of deep despair and fierce love.

It can also be playful, light-hearted, and positive (some people believe). Its motivations are as hard to outline as they are easy to pin down.

If you’re wondering whether or not your partner is cheating on you, read these words.

Otherwise, here are some of the most common reasons why people cheat on those they love—and what you should do about it.

1. Insecurity

Behind every act of infidelity is often a large stomach. Cheaters can crave, salivate, long for something, even if they aren’t aware of it. That something often feeds an insecurity.

My cheating ex nursed a paradoxical need for humility—he hated limelight—and affection.

He shrugged off compliments but hungered for women’s bodies, their applause, their brains. Behind the nonchalance was a desperate desire to be desired—and validated.

This is what led him to maintain at least three affairs at any given time. He flourished on a tide of validating texts, hook-ups, weekend getaways, and unknowing girlfriends, some of them as young as sixteen.

Many psychologists affirm that the need for emotional or physical comfort to fill the wide blank space of private insecurities is one of the biggest contributing factors to affairs.

It’s where the term “emotional affair” comes from, an illicit relationship that feeds an emotional insecurity or need.

People with attachment issues—either fear of it or a disproportionate need for it—are far more likely to cheat than others with a healthy relationship to attachment and commitment.

Every normal relationship does have its own insecurities. Building trust of someone you love is a difficult and mighty endeavor. That being said, not every insecure relationship or partner is a prelude to a cheating mindset.

Yet if your partner thrives off of sexual attention, general praise, and feeling desired—and cannot seem to sustain themselves in a healthy way outside of these things—infidelity could be on the horizon.

Should you stay?

This decision ultimately rests with you.

Insecurities are stubborn weeds, however, and require a lot of self-work before they go away. Someone who is accustomed to feeding insecurities rather than acknowledging and abolishing them is far more likely to keep cheating after one incident.

And well-nursed insecurities can rapidly become unhealthy addictions (and even pathology).

2. Addiction

I’m not just talking about a severe drug addiction, such as heroin, although these can certainly be paired with cheating habits.

Some people have veritable sex addictions, and cheating becomes the mechanism to satisfy an insatiable craving for sexual activity. These can be hard to diagnose and disassociate from a high sex drive.

Yet sex addictions hinge on a foundation of highly compulsive behavior and the persistent need to have more and more sex—with a variety of partners.

Infidelity can thus be motivated by a need to satisfy addictive behavior from a purely physical perspective. Cheating becomes the channel for frequent sexual encounters an individual fiercely desires.

Sex addictions are more common than you may think. Some people estimate that more individuals are addicted to sex than prescription drugs. My former unfaithful partner had a sex addiction.

Should you stay?

The territory of addiction is hazy and fraught.

It is one thing to stay with a partner you want to help out of addictive behavior, but it is another to be constant prey to such acts.

Sex addictions can make loving partners feel unwanted, unworthy, and afraid—states that no healthy relationship can linger in for long.

Sex addictions can also be harmful for your physical health. Sex addicts can acquire STDs of all kinds and distribute them unknowingly.

It may be wise to move on so that you don’t have to play the Savior.

3. Fear of Commitment

It’s easy to joke about commitment and how we all run from it. I think we should just be honest here. The idea of a loving, fulfilling, committed relationship can be downright terrifying.

This is because commitment requires, well, effort. It also urges vulnerability and honesty. Sustaining all of these things for years and even decades can be simply overwhelming.

Some people cheat because of this fear. They may turn to an affair at the moment a relationship deepens and flourishes.

People propose to their partners and then sleep with others the next day (it happened to me).

Commitment also means, in some eyes, dependence. Committed partners may feel as if they are wearing chains and long for the freedom of soaring through an open sky.

An affair has all the allure here of something free, unattached, and arbitrary. It can be the explosive orgasm we all crave without the obligation for serious, soul-searching talks right after.

It’s the reason why over one-third of marriages experience infidelity at some point, from one partner or both.

Should you stay?

If your partner claims to have cheated for fear of commitment, that fear is on them. They will ultimately be responsible for confronting that fear and discovering solutions for eradicating it.

At the very least, this is worth a serious conversation. It may require a discussion about how quickly or slowly a relationship is moving and what you both need to keep it moving.

If you do decide to stay, be sure it’s for the right reasons—and not because of your own fear of living without your person.

4. Revenge

Some people cheat on partners out of pure revenge. This type of cheating can be especially painful because it turns an illicit affair into a power tool designed to manipulate and hurt a loved one.

In some cases, one cheating partner can create another cheating partner. This spiral of infidelity is the result of deep pain and a desire to make the other “pay” for what they did.

Should you stay?

Malice has no place in any healthy relationship. Nor do direct, persistent acts of manipulation. I’ve never been a fan of power plays, especially when it involves sex or a simple desire to harm someone else.

If your partner cheats on you in order to enact revenge of some kind, consider packing a suitcase. At the very least, have a real conversation about expectations and equality.

5. Incompatibility

We all know what it’s like to someone who doesn’t fit you. It’s like finding that pair of jeans on sale at Nordstrom Rack, realizing they’re too small, and buying them anyway—the sale price is so good!

When we realize we’re incompatible in some way with someone we love (or someone we are married to), this realization comes with no small shake of despair.

For this reason, many people resort to affairs with people they are compatible with, at least on some primal level (even if it’s just sex). This type of infidelity is the result of pure hunger for that perfect match, longing for true connection, and a desire to be “seen.”

Should you stay?

Incompatibility can be uncomfortable. There are a lot of sharp edges to navigate. The more frustrated and unhappy both parties feel in an incompatible relationship, the more likely affairs are to surface.

You deserve to be with someone who resonates, like a tuning fork set to the right pitch. Talk to your partner. Talk about your incompatibilities. Most importantly, talk about what you need before you stay or go.

6. Curiosity

The notion of an affair can be tantalizing, especially given how much infidelity is talked up on media. Whisking a stranger away to a private suite in Morocco for a weekend may sound sexy, risky, and fun.

Some people get lost on Tinder, even when they’re in a committed relationship, longing for that quick fire of unknown connection. Affairs can also be mechanisms for exploring sexuality previously untapped.

Infidelity can be the result of mere curiosity in this way. Some people want to know that that kind of risk tastes like. They want to get to know that woman sitting at the bar or that man leaning against a street post, without the eyes of their lover watching.

Should you stay?

This is certainly one of the more tame reasons for having an affair. Mere curiosity for an illicit experience under certain new conditions may not have elements of malice or addiction in it.

If your partner has cheated out of pure curiosity, have a conversation. Perhaps it’s time to talk about having an open relationship or a heart-to-heart about needs and expectations. If you do stay, make sure you also get the satisfy your own curiosities along with your partner.