I started watching this series on evolutionary psychology and the professor, Robert Sapolsky, opens up the class on this one observation on the polarity in species. (You can find the playlist of all of the lectures on YouTube; standford university lectures)

The first pole is the tournament species: High sexual dimorphism, women selecting guys for high quality genes, low lifespan for males, blindly polygamous males, 5% of male reproducing, fidelity from women. The fidelity stems from the fact that the male they chose is of top quality, aka "the prize".

Pair bonding species: Similar build for male and female, selection based on parental qualities, similar lifespan, monogamous pairing, almost all individuals reproduce, females tend to leave the males after reproducing. The males are chosen on their parental qualities, and deemed fit to parent alone; therefor women tend to leave the reproducteur with his descendance, to find an even more parental suited male.

The human is situated somewhere in the middle with variance, some kind of spectrum; so here we cleanly observe the AF/BB dymnamics exposed by a standford professor.

TL;DR: AF/BB, lift , be "the prize".

If this is well received I may do a follow up post on his human sexuality lectures.