Ok.. If we started to let men having sex with us, who are going to take care of our kids? Think about it.
In mother nature, it takes a lot of time to raise and nurse a healthy child so females only can have one baby at a time.
Handsome men evolved thanks to picky females - 12 May 2004 - New Scientist
Sociobiology
"Sexual selection is one form of natural selection
sexual selection is natural selection that favors traits that increase success in mating
two kinds of sexual selection:
intrasexual selection: selection that occurs due to differences in success at mating that result from interactions between members of the same sex
the most common form is male-male competition
such as
males fighting each other for access to females
the outcome of the interaction of the males determines which male mates; the female is not involved in the decision
example:
intrasexual selection might lead to large canines becoming common among males, because the males with the largest canines can drive other males away, so they get more access to females, so they leave more offspring
intersexual selection: selection that occurs due to differences in success at mating that result from interactions between members of opposite sexes
the most common form is female choice
such as
females picking the most desirable male to mate with, based on some visible trait
example: intersexual selection among peacocks might lead to large tails becoming common among males, because the female peacocks prefer to mate with males with large tails, so the large-tailed males mate more often, so they leave more offspring."
"other kinds of natural selection caused by predators, changing food supplies, etc. act more or less equally on males and females but sexual selection acts primarily on the one sex that is competing for the other
that is, it mostly affects males
recall that
female mammals can have only a limited number of offspring, but males
have almost no limit females can generally only conceive when they aren't pregnant or lactating, and even then only during a
limited portion of their cycle males can mate any time
so there are generally
plenty of males around to mate with when a female needs to
but the males have to compete for access to those limited chances to father offspring
so selection will favor any feature of the males that increases their success at mating"
Sexual selection in primates
too.
so don't blame yourself pepe... u probably found wrong guy who u thought will be yours after first date 
It was our first experience hearing and Deaf having sex ! He prefer to staying with his wife. 
He had only having sex with his wife twice a year. 
