There is pretty strong evidence against the submission that is currently at the top of /r/blackpillscience:
Actual link to study: https://www.scraigroberts.com/uploads/1/5/0/4/15042548/2013_little_et_al_pill_pne.pdf (Little 2013)
They only had N=18 women in the control group and 37 in the experimental group, so the small sample size may explain why they got an outlier result.
So this is what they found in much larger studies more recently:
This N=584 study found hormonal contraceptives make the preference for masculine faces slightly stronger, not weaker.
https://www.biorxiv.org/content/10.1101/136549v3 (Jones et al. 2017)
An even larger study N=6482 heterosexual women also could not reproduce the result by Little et al.
No evidence that women using oral contraceptives have weaker preferences for masculine characteristics in men's faces
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0210162 (Marcinkowska 2019)
Blackpill implication: Even when "simulating pregnancy" with a contraceptive pill, women still desire alpha cues in their partners (perhaps even slightly more strongly).
More evidence against dual mating strategy or "AF/BB":
79% of women who have affairs report falling in love with their affair partner, in contrast to only a third of men who have affairs, so there is no evidence that a majority of women would try to get the genes of an alpha in e.g. a one night stand.
It's rare that men bring up other men's children, rendering it also unlikely that dual mating was the dominant mating strategy in the past (this leaves open the possibility that it is a less popular alternative strategy though):
The vast majority of women, perhaps 97% or more, appear to be securing both genes and investment from the same partner
I guess, the question that this in part tries to answer, is what happened to the ~60% of males throughout history who did not reproduce (as opposed to only ~20% of females). It seems the evidence above favors the hypothesis that most of them were simply lonely (tramps, outcasts), died in conflicts, tribal wars or during hunting etc., rather than BB. AF/BB has likely been a relatively minor phenomenon at best.