I am going to put aside the supposed “emotional attachment” that women assign to sex. To me, this is just another myth. It is not a biological fact. “Emotional attachment” is a psychological construct. I don’t want to over-clinicise (sp) this idea. Connection between two humans enriches the sexual experience. Without the desire to connect at a deeper than physical level, sex may as well be mechanically induced. No, the advantage of procreation is only found in variety of mates. That procreative drive is at the heart of male/female sexuality.
We seek partners according to many physical and economical attributes. Those that fit the criteria we desire will most likely be sought out for sexual intercourse. This is, however, limited to the scope of people seeking to create families. What happens to those that dispense with the procreation and seek sexual partners for pleasure?
Procreation can be pleasurable, but it has intent outside of the actual sex act. Therefore, it does not need to be pleasurable to attain the desired results. So sex for fun has to be that. Both men and women are wired for pleasure. This makes sex a desire and procreation a possible result. If progeny are eliminated from the possible results, all that is left is sex for pleasure. Now the point of sex is no longer ejaculation, but sustaining pleasure.
Sustaining pleasure then is about technique. Any browse through the self-improvement section of your favorite chain bookstore will reveal that notion to be true. I found a book on becoming a multi-orgasmic male. (Later, I learned my mother gave a copy to my brother. Sexual hang-ups were never really a problem in our house. Somedays, we wish they were.) The sex manual has been around for centuries. We have been teaching each other what is necessary for pleasure. The invention of positions, condoms, the pill, dildos, and sex clubs, among other things, only goes towards proving that pleasure is important to the human sexual being. We strive to make sex longer and more pleasurable. Duh!