A society that extols monogamy, socially or penally punishes adultry and harem-building, and decries cad-like behavior, exhibits alpha churn. The stronger the social adherence to monogamy, the higher the rate of churn.
Alpha churn describes the evolution of social hierarchies where formerly alpha males devolve into betas through social pressures like marriage. In past times, alpha maleness encapsulated both the provisional and sexual realms. Men were alpha because they had superfluous status, power, and wealth. These men had extra resources to provide for marginal harem-members and children. I’ve heard it said that a woman would rather be the third wife to a first-rate man than the first wife to a third-rate one.
Monogamous marriage has changed all of this to the benefit of third-rate men. No longer can an alpha male convert his resources into more female partners and more procreation. Instead, one alpha female gets all of the glory unless they either divorce or he cheats on her. Both are expensive behaviors and are avoided by men in most cases. A once-alpha-now-married man can still be considered alpha, the only problem is that his lone wife has captured all of his alpha cred and sealed it in a glass jar. It serves no purpose outside of his castle; his alphaness has become local rather than universal.
Monogamy is a great converter: it turns alphas into beta providers. The alpha/beta dichotomy (yes, yes – its not a dichotomy, its a spectrum, but KISS) is relative. Within a closed monogamous system, single men become marginally more alpha when a former alpha marries. Alpha churn occurs when, like lemmings, alpha males dive off the marriage cliff. The alpha goes from being the beneficiary of hypergamy to a monogamous state. The multitude of spoils he could have wrangled are now dispersed to the new alphas that have taken his place. This is alpha churn.