The daddy-at-home theory posits that concealed ovulation evolved to promote monogamy, to force the man to stay home, and thus to bolster his certainty about his paternity of his wife's children. The many-fathers theory instead posits that concealed ovulation evolved to give the women access to many sex partners and thus to leave many men uncertain as to whether they sired her children.
Jared Diamond, Why Is Sex Fun? The Evolution of Human Sexuality
monogamy, ovulation, sex