I've never heard of a culture that shames people for being too stingy with sex.

"Come on. Everyone is doing it."

"Don't be a prude."

"What are you, gay or something?"

"He cheated on you? I guess you weren't doing enough for him."

"A wife must satisfy her husband."

"Frigid."

Social standing is awarded to women with many children.

Spousal rape was legal in some US states as recently as 1993, the first state outlawed it in 1975.

And so on. Which is to say cultures discourage certain kinds of sex in certain contexts and encourage others. Subcultures differ in the degree to which they encourage and discourage sex. It may not be that the human sex drive is too strong for humans in society but that biology lacks the precision guidance of cultural norms which can perhaps support more complex reproductive strategies or change faster in response to new economic circumstances.

It may well be/have been in the reproductive interests of women to have no sex before marriage and then lots of sex with her husband, for example. One way biological and cultural evolution could implement this strategy is by lowering the female sex drive to ensure chastity until marriage, and then rely on cultural expectation and the male sex drive to encourage sex within marriage. Though I recall a study indicating that women require more familiarity with their partner for arousal than men require. I can't find it though, and of course it coincides with cultural stereotypes. But this would suggest that the monogamous sex strategy for women is implemented biologically as well.

Note also that the shame associated with pre-marital sex is traditionally much stronger for women. Men are often lauded for their sexual accomplishments. Which is something you might expect to see as a difference in mating strategies after considering the relative cost of reproduction.

I don't have it handy to grab specifics, but Sex at Dawn discusses a couple dozen different cultures in which promiscuity is the norm. Some of those cultures shame the non-promiscuous, to varying extents.

Human society as we currently know it is less than 10,000 years old. That's an incredibly short timescale for major evolutionary changes.

From my reading of the anthropology literature, some cultures are sex-positive and some cultures are sex-negative. The first google hit for "anthropology sex positive" is an anthro textbook which lists a bunch of examples of different attitudes towards sexuality, including some where it is encouraged and considered odd if promiscuity is not pursued.

(In the ancestral environment) If a higher sex drive among women is correlated with cheating, there would be a selective pressure on men to prefer choosing women with a lower sex drive as "long term" mates. In a culture where having a reliable mate is key to the welfare of a women (or her children), this could lead to selective pressure on women to signal low sex drive (and saying "sex is bad, especially unmarried!" is one way of of doing that).

This is consistant with the fact that sex drive in women is frowned upon more in women than in men.

One reason could be that reduced sex drive is selected for at the level of the group, while higher sex drive is selected for at the level of the individual.

Assuming for the sake of discussion that this actually is an observable effect, I would expect it to arise because restricting the reproductive success of others is ancestrally adaptive for individuals, and one way of doing that when one is high-status in a group is by establishing/supporting cultural norms that suppress sex by those of low status. It would follow that many groups would establish anti-sex norms to which the high-status elite were exempt.

Memes exist to benifit memes. It's not true that memes necesssarily benefit DNA genes. Rather they often compete with them for resources.

Those resources often include energy which could be spent on sex. So: priest memes, often sterilise the priests, and divert their reproductive resources into making more priest memes - rather than more priest DNA.

people are discouraged from having sex as often and with as many people as they want to

In most cultures I'm familiar with, this is much more true of women than of men.

I'm not aware of any culture where the norms for sexual behavior are the same for men and women (though I wouldn't be surprised if that was the case in some hunter-gatherer tribes or hippie communes). The discussion may be less abstract if we separate "norms for women" from "norms for men" - I suspect traditional sexual norms for European women are closer to traditional norms for Chinese women than traditional norms for European men ("traditional" being say "a village in 1700").

I've never heard of a culture that shames people for being too stingy with sex.

Huh? those same cultures (e.g. Western countries in the Victorian Era) did shame people for being too stingy with sex -- they were expected to have lots of children, and so made birth control very taboo (even the calendar method). Not having children (even for men) was considered an abrogation of responsibility. (A president of a Mormon college recently had very nasty things to say about men who are unmarried and over 25.)

In current, conservative churches, one pastor gave a lecture encouraging married couples to have more sex, and I heard about a different such church on the radio that was promoting the same message. (See also C. S. Lewis's discussion of the awesomeness of sex within marriage in Mere Christianity.)

The sex they condemned was sex outside of marriage, which, given the technologies at the time, did have significant risks. Now, there is good reason to debate the magnitude of these risks, but it's not some kind of bizarre phenomenon.

My guess:

For various reasons, people want things other than children. High sex drive is an adaptation that would encourage people to have children even if circumstances are less than ideal; it's not very good for you to be 14 years old, unmarried, and pregnant, even if it ends up being good for your DNA. (Humans seem to have a lot of adaptations that encourage "unplanned pregnancies"; once we had brains capable of choosing to delay reproduction, maybe we ended up with various adaptations to make sure we reproduced in spite of our forebrains?)

I would guess that the culprit is the difference between speed of technological advance and biological evolution.

As we have become richer in resources and free time, we both have the option to and the tools required for overstimulating any of our "drives" (sex, apetite for eating food, socializing online), without having had the time for individual level evolution to catch up. We see adaptations at the group/cultural level because changes there happen more quickly, and are easier to notice. If the pressure remains sustained for a long enough time, we'll see biological changes, too.

from what I remember from my human evolution classes, promiscuity allowances is very much related to resource availability. Google: Robin Hanson's "forager vs farmer" this has some of these ideas.