It's relatively recent that women are able to make that decision, or to reliably make the decision of whether sex is related to reproduction.

Often less, and it's more "expensive" to them in a no-contraceptives world because men don't get pregnant, and they (historically?) also had an unfavorable "workload/child" burden compared to the husband in general.

Women don't necessarily want to have children... You don't have to plant seed in the field every time you plow it.

Also women's choice and reasoning behind mates tends to be different from the male section algorithm.