I do not agree with the idea of sex having become pleasant to humans, in order to encourage us to reproduce, and help the process of survival. I believe finding, and seeking, gratification in sexual scenarios and practices, and being passionate about the other possibilities of mating activities, are the inevitable fruit of another evolving phenomenon: the human brain.

It is, indeed, interesting that the pleasurable act of reproduction among humans could have played a role in our survival, as a type of species, on this planet, but I definitely do not see any relation between a coincidental fact and the way humans perceive, understand and experience sexuality as an enjoyable matter, because there have been many people who have found close to zero appeal in sex for various different reasons, but have still managed to reproduce fairly well, throughout our history.
At the same time, many sides of human sexuality have almost nothing to do with breeding and survival.

Religious texts are good sources for studying the perspective of a group of individuals, which usually happens to be a dominant force in their society, in regards to this subject at certain points in our intellectual evolution, which is directly related to the evolution of the brain as a computational organ at our service.


There can never be any certainty about the past history, since not everything has been documented, and not all that have been, have survived up to an age when they could be known to a wider group of people, and analyzed by more experts.
It would be a good idea to model the different historical facts known to us. After an exhaustive analysis, assign a different term, of a different weight, to each fact, and use predicting algorithms to verify the past (which would not be difficult to test on the past few hundred years since more information about the different states of the planet and humans has been documented), and foresee the future.