Many other species have multiple partners, but are humans meant for monogamy? Plus we ask, do flies have a super sense of smell?
I believe it is reasonably well established that humans have a strong tendency to be serially monogamous. The divorce rate would support that notion. Note that divorces could not occur without marriage (blindingly obvious) and that marriage, common as it is in some form in many (most) cultures is a formal societal recognition of the tendency to be monogamous. Thus the divorce rate itself supports the notion of the serial aspect.
Compared to other primates, we aren't the most promiscuous but not the most loyal, either. Humans apparently fall into the "sort of monogamous" category, with pair bonding behavior and the occasional dalliance.
I would wonder if the question is different for men and women.
With suggestions that within a decade we should have 100% DNA sequencing of babies at birth (or before), the frequently unspoken question/fear about "Who is the father?" will no longer need to be asked.
There may be some things that it is better to not be informed of.
Historically, marriage might have slowed the spread of diseases such as syphilis, gonorrhea, HPV, and etc, many of which are now treatable or preventable.
I think it's important to note that "evolution" only really cares up to the age of reproduction. Males tend to be able to reproduce successfully for longer than females can (anecdotally in my head, anyway. I wouldn't mind seeing the exact number on that), and therefore the drive to seek out other child bearing females may be stronger (that's no excuse of course!).
The percentage of people living past their mid 40's during prehistoric periods may have been small, so a loss of fertility may not have been that significant. However, there may still have been evolutionary benefits of selecting younger wives, including finding a wife that was likely to live and contribute until the child was an "adult". CliffordK, Thu, 14th Feb 2013
An analysis of mobile phone records showed that beyond a certain age, a woman tended to shift her main communication channel from a male of similar age (presumably husband/partner) to a woman of younger age.
One of the basic lessons of Darwin is that the fate of any species depends on how well it adapts (quality) and on how well it reproduces (quantity). My observation is that the male and female brains are differently hard-wired: the female primarily for quality issues, such as natural selection, while the male brain is assigned the solitary task of quantity. This is apparent in most mammalian social orders: primates, big cats, livestock, etc. but for the most part suppressed in humans.
Monogamy is a concept that is only valid in species that reproduce sexually and usually where there are two distinct sexes (i.e. barring hermaphroditic and sex-changing species.) The distinction between nature and nurture/learning as the predominant impetus for monogamy is blurry. Take, for instance, penguins, which are extremely monogamous. In their extreme environment, it may be understood that the rearing of a single offspring may take the lion's share of the work-effort of two parents, and it is the reproductive best interest of both parents to raise the offspring together. A successful pairing is evidence for future a successful pairing with the same partner in the next season. On the other hand, take the case of a stallion. The environments are not as harsh and the populations have the luxury of wide expanses/ranges. In this case, the reproductive strategy for the male would be to mate with as many females as possible in order to assure a higher likelihood that one of the matings will produce their own offspring and to ward off or kill potential cuckolds. In western cultures, this behavior would be construed as promiscuity and (what I would call) ‘sexual-jealousy. The male cannot ever be certain that the product of his pairing with a female will be his own offspring. In the case of the female, she is assured, 100% of the time, a successful mating will forward her genetic heritage. However, during gestation, her physiologic needs and her vulnerability begin to rise as she must nourish the developing fetus and subsequently nurse it and protect it after birth. Any manner in which the female can bond and recruit the assistance of the male would be of tremendous survival value. If the male ‘wanders’ and distributes his attention among several females, the amount of support becomes diluted. Hence, the root of what I believe may be considered among the cognitive beings of western cultures as ‘emotional-jealousy.’ Empirically speaking, I think most men would recognize that they do not necessarily connect sexual relationship with emotional love, at least nowhere as nearly as do women. On balance, it is so that, among humans, the concept of monogamous relationships is largely cultural and learned. It is not natural for human males to be monogamous. As with other herd animals, the only way that a male can be most assured that an offspring is his own, is to pair with more females. For females, there is the assurance that 100% of the time, their offspring carries forth their genetic heritage. Sal Napoli, Sat, 16th Feb 2013
It would be interesting to see a statistical distribution of the answers and comments you get here, between men and women. My bet is that far more women will contend that monogamy is the natural order of things. Sal Napoli, Sat, 16th Feb 2013
I'm seeing statistics all over the ballpark. But, keep in mind that it isn't only the men that cheat. And, cheating necessarily involves 2 people. I.E. If married men are having affairs, then there are also the women who are having the affairs with them.
What if the spousal selection criteria does not promote monogamy.
I think the well-intentioned OP began with a false premise about divorces.