Why do men cheat? ( The scientific view)

Is it a truism that once a cheater, always a cheater? Are men more prone to cheating or are they polygamous in nature? Are they truly attracted by what they see? Many women have asserted that it is difficult for men to stay with one partner, that men are "dogs" and needs a strong woman to keep them in check. Well, the question is are most men cheaters and if so, what is the reason behind this issue? Can science provide the raison d'etre as to why this type of behavior?

It is reasonable to assert that relationship issues are quite complicated and people see cheating in different perspectives. Let me start this post with this short funny conversation below between a certain "Husband & Wife"

WIFE: Honey, Since we got married, how many ladies have you slept with?
HUSBAND: (quiet)
WIFE: (15 minutes later) Honey, I asked you a question & still waiting for your honest answer!
HUSBAND: (Quiet)
WIFE: (20 minutes later) Why are you still quite, are you afraid to tell me the truth?
*HUSBAND: Will you just shut up and let me finish counting!!!

Hmmm, If you were in the wife's shoes, I wonder what will be going on in your mind...

Image source

Interestingly, according to Dr David Buss from the University of Texas in an interview posted in MailOnline;

'People cheat for many reasons—because they are bored, for sexual variety, for revenge, because they are emotionally or sexually dissatisfied, for adventure, for resource, or as a mate switching tactics,'
More so,
'The reasons are almost as varied as the reasons that people have sex in general,' adds Dr Buss, who is the author of the book 'The Evolution of Desire: Strategies of Human Mating.'

However, there is a wide gap between what male and women see cheating as. In Libby Plummer's own contribution in Mailonline, "THE GENDER DIVIDE"

Only 34 per cent of men consider sexting to be cheating, compared to 49 per cent of women says law firm Slater and Gordon.
Women are more likely to cheat because they are seriously unhappy with their primary relationship, loneliness, or in a subconscious search for 'better genes'.
They tend to be more upset by the emotional aspect of cheating rather than the physical side.
In contrast, men are more likely than women to cheat for pure sexual variety and sexual motivations, say the experts.
Males are more likely to define infidelity in strictly physical terms, are tend to be more upset over the thought of their partner being with someone else, rather than the emotional betrayal.

Read up more from source

However, can science tell us why men cheat?

According to Prof. Paul J. Zak, of Claremont Graduate University and the author of Trust Factor,

There are three hormones that modulate monogamy: oxytocin, arginine vasopressin, and testosterone. Oxytocin has been shown in animals and humans to sustain pair bonds in males and females through its release in the brain during sex, touch, and nearly any positive social signal. Arginine vasopressin motivates mate- and offspring-guarding in male socially monogamous mammals, an important aspect of pair-bonding. Testosterone is associated with libido and many of the male characteristics like musculature and drive that are attractive to females when seeking high-quality male genes.
Furthermore,

The distribution of oxytocin and arginine vasopressin receptors in the human brain reveals that we are a monogamous species. But is that socially monogamous or sexually monogamous? The large size of the male testicles and shape of the penis suggest that we evolved when females would have multiple sexual partners and it was a "let the best sperm win" all-out competition. We have socially monogamous brains but sexually promiscuous genitals.
More so, for Prof.Paul,

Testosterone is in conflict with the bonding effects of oxytocin (literally--testosterone inhibits the uptake of oxytocin by its receptor). It motivates men and women, but mostly men who have five to ten times more testosterone than the fairer sex, to seek more sexual partners (and to be single-minded and to take more risks). Testosterone levels also respond to our social environment. For example, your testosterone goes up if you win a chess match. If you earn a million dollar extra bonus at your hedge fund, your testosterone is likely to go up. If you win the Grand Slam or Master's tournament, your testosterone soars.
So, are high testosterone men to blame for cheating? Certainly. Do their physiologies and abundant opportunities to cheat provide a motivation to do so. Certainly. Cheating by males--especially high testosterone males--is unlike to disappear. We can still recognize its negative impact on women and families, but I see no reason to demonize promiscuous men, even if it feels right to do so