Doesn't indicate if it is a man or woman writing. But I agree with your answer. Oh we are "programmed by evolution" to want sex too.

Yes, you are, but it is different. Men are driven by the need to spread their sperm to as many women as possible to produce as many offspring as possible. Women, on the other hand, can normally only carry - and then nurse - one baby at a time. (That is true in nature, where if twins are born, one is usually left to die.) So women tend to look for one mate - it is why, for example, women tend to be more verbal, men more visual, when it comes to sex. The woman is looking for comfort - for a male that will produce healthy offspring and protect mother and child from rival males and predators. (Before you flip out, I speak here of man as animal in nature. Obviously human beings transcend nature and evolution. We start with instinct but move beyond it if we are properly raised and socialized. So I speak here of tendencies in human behavior, not absolutes.) Anyhow, there are biological "leftovers" from our evolutionary past. The reason why men tend to get sleepy after sex - and why they MUST orgasm to ejaculate sperm - is that it keeps the male closer to the female to facilitate bonding. A man's testosterone level will tend to rise in response to his mate's pregnancy. (She secretes pheromones that change over the course of pregnancy and after birth. Males react to her body changes and their physiology and psychology involuntarily respond to these changes.) This is a leftover - our prehistoric ancestors had to be prepared to ward off rival males so as to protect his unborn offspring, Yet after the woman gives birth, her pheromones subtly alter again and the man's testosterone levels will tend to drop for a time. This is because an aggressive male would A) have a tendency to be a threat to his own offspring - in nature, some primate females tend to drive the male away after birth - and B) not stick around after birth but begin to seek out new females to impregnate. (In nature, the more babies a male makes, the more that are apt to survive and perpetuate his DNA and the species.) Of course, after a while, the male's testosterone begins to rise again, but by that point, if all goes well, other emotional bonds develop - plus the assurance of regular sex - to keep him around. As a sidenote, one of the reasons you tend to see higher rates of child abuse by stepfathers is because, as the male was not around during the pregnancy and birth, his testosterone does not go down. In evolutionary terms, those babies are rivals for resources to his own (potential) offspring. So the male will be more aggressive and less nurturing to his stepchildren. So, yup, women are programmed by evolution, too - but in VERY different ways.