In the past, natural selection was understood as the "survival of the fittest". Today we understand adaptive success as the ability to pass on our genetic material to the next generations. The more replications of our genetic material, the more adaptive success. Sounds like more fun, doesn't it?
From the point of view of natural selection, the most important quality of any living organism is its "fitness", which is nothing other than its the statistical probability of transmitting its genes to the next generations [1].
Obviously, in order to pass on our genes, we would have to meet a series of intermediate challenges, which can be summarized in four: surviving at least until we reach sexual maturity; being able to access sexual partners and reproduce successfully; having our children and relatives survive until sexual maturity; and establishing reciprocal collaborative links with unrelated individuals in order to increase our chances of survival.
The intense emotions associated with our own survival, with motherhood and fatherhood, with "falling in love" and finding a partner, with establishing a home, and with bonding with our closest relatives, would be a reflection of how the brain has evolved to "mobilize" us to ensure the transfer of our genetic material. The basis of these emotions is linked to the nucleus of our brain and operates quite automatically[2]. On top of that, we can always add a little bit of romanticism. One thing does not rule out the other.
With this new logic, not only the strongest would multiply, but also the most astute, the most cautious, the most daring, the most peaceful, the most creative, or anyone who would achieve a reasonable number of living children, whatever their method. And although we still have much to understand, many studies already confirm this suspicion: our personality influences our "reproductive success"[3].
[1] Penke, L., Denissen, J. J. A., & Miller, G. F. (2007). The Evolutionary Genetics of Personality. European Journal of Personality, 21(January), 549–587. https://doi.org/10.1002/per; Sapolsky, R. M. (2017). Behave: The biology of humans at our best and worst. New York, NY; Penguin. [2] Sapolsky, R. M. (2017). [3] Penke et al., 2007