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The queen, in all her guises, must always be served.
Human mating characteristics mimic those of birds. Monogamy is as much a social construct as it is a genetic one. Polygyny is still relatively common and tends be cultural rather than genetic among humans - much like many species of birds.
This also explains the high rate of infidelity and why, worldwide, around half of the children born are not born to the 'political' father, but to some interloper.
Because a male in a political union is just as likely to pick up a mistress as one who is not (and that woman will compete with her for attention and resources), women developed "stealth-ovulation" to ensure that any man who wanted to guarantee pregnancy would be forced to mate multiple times. Thus - it was a way of dominating the male's time and forcing him to be more committed to his mate.
Also, as males became more intelligent - it was quite likely that females who expressed signs of ovulation were more likely to be fought over and less likely to successfully reproduce - which would not just make "stealth ovulation" beneficial, but "overt ovulation" would become detrimental.
No single trait we have is the result of one single 'thing' - though most can be traced back to one or two key drivers that comply with the Red Queen Hypothesis.