A near universal trait of human societies is that they construct moral systems and social norms which reward monogamy. This is because a highly committed family structures which encourage cooperation and low time preference are obviously going to be more productive and useful to the civilization as a whole. Monogamy is the only option which has a rigid and generally effective long term plan for the happiness of both parents and offspring, that's what makes it uniquely sustainable. Every other option has low commitment and high time preference which will often result in particularly polyamorous people running out of chances to enter into a stable family unit once they naturally age out of desirability, leaving potential children poorly raised and many individuals unhappy, a much less sustainable approach. For these and many other reasons civilizations benefit from monogamy because the long term well-being of the population is kind of the point of civilization to begin with. The only challenge regarding monogamy is that it is difficult to practice in the short term because humans will often have many options to choose from and committing to just one can seem pointless. This is why traditions had to be formed to encourage monogamy for the sake of its long term benefits in spite of its difficult short term implementation. This is the anthropological case for monogamy.
In today's hedonistic and high time preference society marriage is understood improperly, relationships in general are used for short term pleasure more than long term fulfillment. When the short term pleasure inevitably loses its excitement relationships then lack the commitment to continue for the long term. This leads to a hedonic treadmill effect where people are in a cycle of pursuing short term pleasures that leave them spiritually unfulfilled, this unfulfillment drives them to pursue even more short term pleasure to fill the void. Basing a relationship on pleasure in this way causes people to build highly specific tastes which become harder and harder to satisfy, this approach reduces the willingness to commit to relationships the more it is used. These tendencies often continue until it is too late to reverse their effects. In this situation an unreasonable amount of the civilization's total effort is expended in the pursuit of poorly understood pleasures. I wrote a related article on this form of hedonism here.
What is different about monogamy that makes it superior for long term psychological well-being and the success of our culture and civilization? Analyzing some of the marriage practices of traditional societies will help us to understand this.
Traditional practices include:
* 1. Social support is given to monogamous practices and moral disapproval for failure.
* 2. Marriages heavily favor a specific in-group.
* 3. Marriages involve gender roles.
These traits combine to incentivize longer term monogamous relationships that are more fulfilling.
The first point demonstrates how social pressures from one's community encourage both parties of a relationship to commit as much as possible to its success. To have an unsuccessful marriage or to not seek marriage at all is often to bring shame upon your family and community. This effect only really happens when both parties of the marriage live in cohesive communities. The heavily industrialized and populated modern world doesn't tend to inspire a cohesive and tight-knit community unfortunately. Assuming the presence of a healthy social environment, marriages will tend to be more committed. This confirms that there exists an important but often forgotten relationship between the larger community and the smaller married unit. Marriage should be understood as the creation of a unit which is the result of and a participant in the greater community, not just the union of two arbitrary individuals.
Small towns with cohesive populations statistically tend to have high marriage rates but low divorce rates. When your moral and social environment enforces specific marriage guidelines your options are narrower and your commitment within those options necessarily increases. Commitment is important in part because it enables us to tolerate the unavoidable flaws and imperfections of our partners and ourselves in the pursuit of a greater fulfillment. The core principle of monogamy is a proper humble commitment. This resembles the way the christian God provides spritual fulfillment and the forgiveness of sins if we partake in a commitment with Him, which explains the tendency for marriage to be associated as a religious practice. Without commitment, flaws can be viewed as an opportunity to seek another partner. This suggests that commitment is an often neglected element of any relationship. Rituals such as weddings serve to maximize commitment but because of that those rituals become less appealing to the increasingly hedonistic average person and are then performed much less often in society.
The second point shows how in-group preference benefits marriages. Social pressures from one's family and community will encourage them to only marry within their in-group, or the marriage will just be arranged instead of pressured, in which case it will be arranged with an in-group in mind. Some in-groups involve religion, homeland, ethnicity, or more. One must be a participant in a cohesive in-group for this effect to work so living in a highly individualistic environment like a big city isn't ideal here.
This preference ensures that partners have high compatibility, since people within the same in-group will share many more obvious and subtle similarities than they would with a random person. The success of relationships can sometimes be predicted by genetic similarity alone, not even including social similarities, so keeping to your in-group is good advice. This can be contrasted with the statistical tendency for more diverse towns to have high rates of single parenthood.
In-group preference results in marriages which are more consistent with the social structures of the community surrounding the marriage. When the marriage is viewed as a participant in a greater community it will receive helpful social validation, which aids in its success. In massive industrialized non-communities it is difficult to find such social validation, this forces marriages to validate themselves in an isolated fashion, which is more difficult.
Marriages which are subjected by the community to unambiguous guidelines have high levels of commitment because they are driven by a duty to satisfy family and community on top of already being driven by the personal need for partnership. As well, the nature of this situation reduces your options for relationship partners in the first place. A reduced number of approved options increases the commitment you have with the option you do end up with, that's the psychology of scarcity. You will struggle less with the temptation to break commitment when those temptations are understood to be outside your selection of options at the moral and social level.
The third point showcases how a marriage can become dependent on itself and therefore become self-perpetuating. A symbiotic relationship between gender roles guarantees that each partner is dependent on the other for certain needs, whether emotional or task oriented, and will therefore be more likely to strengthen the relationship than abandon it. In recent times gender roles have been deconstructed to the point of being almost nonexistant, most women are in the workforce now and many men are neglecting their duty as family leaders. In a world where both sexes are viewed as entirely equal in every way, symbiosis between them becomes impossible. See this post for much more detail on this topic.
The rationalist may view many of the traits of traditional marriage as arbitrary social constructs, but as you can see these practices do serve actual intentional purposes which have huge benefits in reducing the divorce rate and increasing the long term fulfillment and happiness of couples who conform to tradition. The original purposes of traditions are easily forgotten in this modern world where there is so much new information to distract us from old information. This causes people to dismiss traditions as arbitrary social constructs that needlessly restrict their personal freedom, specifically their opportunities for sexual pleasure. This is why I believe it is very important to study and understand the functional origins of traditions so we don't fall for the distractions of modernity and forget the traditions which guide us. We don't practice tradition just because it is tradition, we practice it because it has a valid function and because it is Lindy. This Lindy Effect validates tradition more than tradition's modern alternatives.
There is so much more to analyze regarding marriage and tradition but those are the few points I have the confidence to write about in this post.