How can couple’s protect themselves from affairs? What are the signs that someone could stray? Explanations range from a lack of moral character ("a jerk") to the biological (men are just built to spread their seed). But these conclusions are too easy, too knee jerk, especially when one factors in the more complex emotional and psychological layers—layers that can’t be quantified as "fixed," like the biological (which, if it were inviolate would mean that all men cheat and can’t help themselves).

I think the better we understand infidelity, the more marriages can be protected or saved. Infidelity isn’t just sexual, it’s emotional. I frequently hear from men who stray that they love their wife, that they don’t want to leave her and that the reason for the dalliance is not because she isn’t enough. In therapy, I take a look at the way a man behaves in relationships: how they bond, how they communicate, how they manage their emotional needs and yours. Here are four (of many) overlooked states that can lead to infidelity:

Anxiety
Some men get so nervous about their sexual performance that they end up with erectile failure, then avoid sex with their wife and seek out sex services like massage parlors or prostitutes. One individual in my book, Paul, escaped from the pressure to be a good lover to his wife by going to places where he could relax and just enjoy the pleasure. Again, this doesn’t mean all anxious performers will cheat. One irony: anxious performers don’t always appear anxious. Paul was confident in all areas of his life—except one. Falling in love made him anxious.

Power Seeking
A power hungry man may or may not have achieved a powerful status in his life, but either way he wants to feel dominant and he uses sexuality to access this sense of himself. The actual sex doesn’t matter as much as the interaction. The act is about having the woman as supplicant, and occasionally degrading her. These guys aren’t looking for love. They want the disadvantaged, the economically desperate, the drug-addicted, and the under-aged. Their vulnerability makes them more attractive because they are exploitable.

Excessive Pleasing
This man is catering, nurturing and kind. He never starts a fight. This creates a need for personal space where he can be himself. He may spend a great deal of secret time looking at porn or hire a sex worker so that his needs will be taken care of. He is unlikely to take the risks necessary to keep a relationship erotically creative for fear of her disapproval. Further, in relationships where either the husband or wife pleases to the exclusion of his or her own voice, sex drive will disappear.

Narcissism
Narcissists relate to women as objects to meet their needs. They will expect their wife to be the source of all care, adoration and comfort. He doesn’t meet these needs for himself well and isn’t able to provide them for others. The quality of the bond he creates is shallow. He does not allow people to matter, does not connect deeply. He views people as easily replaceable, able to move from relationship to relationship with little emotional effect.

He may have immature expectations of relationships, "She should give me love or sex, when and how I want it or I will be outraged." If this belief is combined with a general tendency to be impulsive and a lack of communication; then you have an increased chance he will act out instead of talking to you.

In part, the socialization of young men sets them up for this unique set of issues. They get the message in adolescence that it isn’t okay to be emotional, but it is ok to be sexual; increasing the likelihood that they will use sex to act out emotional issues. They get the idea that they should have as much sex as possible and that they should separate sex and love, increasing the likelihood that men will approach women for impersonal reasons of status on exploitation. They are supposed to be dominating, have erections that never fail and they must please the woman setting them up for anxiety.

In general, men value intimacy and commitment. They don’t approve of cheating and don’t typically set out expecting to. The best ways to prevent infidelity are to set the space for honesty and communication early in your relationship. Discuss expectations and disappointments. Talk about the quality of your sex life. This way, all of the emotions that come up in relationships are dealt with in words, not destructive actions.

Dr. Brandy Engler is a licensed clinical psychologist specializing in  relationships and sexuality. After years of training and practice in New York City—including working with a  crisis team on the streets of Brooklyn, and her own private practice in Times Square—she headed West in search of greener pastures. Los Angeles isn't quite green, it's a bit dustier than imagined, but Dr. Engler traded in her metro card for a car and is enjoying road trips across California, where she's discovered many pastures, lakes, and mountains and.... a husband. Dr. Engler now has a private practice in Los Angeles is author of "The Men on My Couch: Stories of Sex, Love and Psychotherapy" and is currently finishing her second book. For more information check out her website www.themenonmycouch.com.