I watched an aging documentary in a first-year bio class that addressed this issue, and it is viewable online. It deals with the burden of theory faced by evolution in the explaining of human monogamy and community. The documentary contains nudity and, as such, I will not name it here; but here's the gist... (I'm no scientist, and will neither support nor tear down the idea. This theory is at least 20 years old and surely is more nuanced by now, if the scientific community still subscribes to it)...
Evolutionary theory suggests that marriage and (usually) monogamous couplings occur because, for some reason explained by other evolutionary traits, humanity thrives best in such a grouping. There are examples of monogamous life-pairings elsewhere in nature -- so humanity is not unique in this regard. The ceremonies, fashions, flirtatious behaviours, and cultural customs surrounding coupling, marriage, mating, and family have parallels in nature, though obviously not to the degree that humanity does. I think evolutionary theory would suggest (and 'suggest' is the key here... I've rarely met a scientist so militant and presumptuous as to call it fact...) that the divine imperative that humanity invokes - meaning that many cultures look to a god or gods who sanction or command marriage - has more often than anything else produced the lasting and stable relationships from which healthy offspring can be produced. In other words, people stay together with greater endurance when they think a god has told them to.
Put another way, human children, like the offspring of primates, thrive within protective and nurturing family units. The future of the species depends on the children thriving. The best odds for these family units developing is within committed and (usually) monogamous relationships -- though this is cultural. These units become "marriage" once filtered through cultural specificities, which includes religion.
At some point, we care less about the demands for survival, and marriage becomes a phenomenon of its own -- for continuance of culture, perhaps. It's arguable that the conditions for healthy growth and the successful passing on of genetic stuffs still occurs in marriage, though this is not unequivocal. Evolutionary theory, when approached with an open and inquisitive mind, is very complex and nuanced.
I have no academic sources to back this up, and I acknowledge that it is very simplistic. It doesn't take into account the challenges offered by cultures that don't value monogamy (tribal Africa, for instance), or how marriage-based family units may nurture unfit or sickly children to the detriment of the family -- threatening survival. Feminist theorists argue that marriage is an institution created by men to institutionalize the oppression of women, and evolution can support or argue this.
Perhaps I can be more helpful if you tell more about what you're looking for -- but keep in mind that I am a student of literature... not science. If you want, I can PM you the name of that documentary.