One thing to keep in mind - perhaps more so in regards to hooking up and relationships than the institution of marriage - is how pair bonding works on a neurological level.
Pair bonding is a (fairly) well-understood phenomenon in terms of human neurology. Primarily through sexual intercourse (but also through other actions, such as affectionate physical touching) both male and female brains release certain chemicals - primarily dopamine and vasopressin in the case of men, and dopamine and oxytocin in the case of women.
Dopamine is the "reward" or "feel-good" chemical. It's what makes people enjoy sex so much, and is the cause of the "afterglow" effect many people report after successful intercourse. In people with a penchant for hormonal addiction (e.g., compulsive gamblers, sex addicts) it can lead to addiction. Simple enough.
Vasopressin and oxytocin, meanwhile, are the primary chemicals that create the "pair bonding" effect - what you might call long-term love and affection, and a desire to stay with a particular partner. However, they do so in rather different ways, which means the whole pair bonding phenomenon works out differently for men and women.
The basic function is the same - vasopressin and oxytocin both bond with certain receptors in the brain which, when stimulated, create the pair bonding effect. However, oxytocin creates a "strong" bond, whereas vasopressin creates a "weak" bond. The receptors are the same, however, so the "maximum" pair bonding remains the same between sexes - it is simply getting to the point of maximum pair bonding that works out differently. Long story short, men require more acts of sexual intercourse with a particular partner in order to begin, and "max out", pair bonding when compared to women.
So what does this all mean? Well, when taken in conjunction with empirical research done on people's pair bonding ability over time and with multiple partners, some interesting facts come to light. First, I'll start with the stuff that's the same for both men and women.
The pair bonding receptors are not unlimited in either number or function. In other words, humans are neurologically limited in terms of overall pair bonding ability. That is, how many times they are able to pair bond, and how strong those bonds are, though the exact limits vary from individual to individual. Researchers have studied this and come up with the following numbers (again, there being some variation between individuals):
At somewhere around 3-5 pair bondings, the pair bonding ability starts to noticeably degrade. That is, each subsequent pair bonding is weaker than the one previous.
At somewhere around 10-12 pair bondings, the pair bonding ability becomes unnoticeable to the point of being virtually non-existent. At this stage, pair bondings are effectively no longer possible, though previous pair bondings remain, if somewhat weakened with time when lacking regular sexual intercourse with the bonded partner.
(Regular sexual intercourse with a bonded partner keeps the bond strong and keeps it from degrading.)
Now, here's where it gets different for men and women:
Because female brains release oxytocin, and male brains release vasopressin, men and women form pair bondings at different rates.
For women: 1-2 acts of sexual intercourse with one partner is normally enough to begin pair bonding.
For men: Anywhere between 2 and 5 acts of sexual intercourse with one partner are required to begin pair bonding.
So what does this difference mean in practice? Well, in simple terms, it means that men's pair bonding ability is less detrimentally affected by hooking up with many different partners when compared to women's, as long as the men only hook up once, or perhaps twice, with the same partner. For women, however, more often than not a single act of sexual intercourse is enough to begin pair bonding. This, in turn, means that women will reach the "limit" of their pair bonding ability much more quickly than men when they both engage in hook-up culture.
In short, modern hook-up culture is far more detrimental, on a neurological and emotional level, for women than it is for men. By the time the typical woman has moved on from casual flings and decides she wants to settle down and have a family, more often than not she has long-since lost the ability to pair bond, making any long-term relationship one of emotional and sexual dissatisfaction, which in turn leads to infidelity and/or the ending of the relationship.
This phenomenon goes a long way to explaining why there are so many single mothers these days, doesn't it? Of course, the state effectively enabling it via social welfare programs and forced child support doesn't exactly help.
Now, in theory - given how other neural receptors have been shown to work - it should be possible for prolonged abstinence from sexual intercourse to (very slowly) restore the pair bonding ability. However, to the best of my knowledge, no empirical studies have been carried out on the subject, given both a general lack of parties interested in funding it and researchers' difficulty in finding enough people who've had 10+ pair bondings and were also willing to spend years without engaging in sexual intercourse (feel free to direct me to such studies if you know of any).
Really makes you think, doesn't it?
