There's a book by Michael Gurian that came out called What Could He Be Thinking. Twenty years of neurobiological research, and what do they find? Men get a massive dose of the "I love you" drug shot into their bloodstream right after they come. Sex and no cigar means no cuddly feelings. One spritz begets the other.
Us girls, on the other hand, get ours from just the rubbing of bodies. No orgasm necessary. I just like to cuddle.
And this is news in science.
There's more. The guy spritz is short lived. A few hours and his body chemistry is back to normal. No special feeling of closeness until the next time. Gals get a higher dose of attachment drugs that last for days. Biochemistry is making her yearn for his company morning, noon and night. Such a gal is not crowding her lover, she is being driven by Mother Nature's 100% organic brand of Ecstasy to crave his company.
Why don't we both get the same juice in the same amount so that perfect love can thrive? Why, you ask, should Mother Nature be so unequal in her chemistry? Mother Nature is wise, and having created your male to go to work to provide for gals, she's not going to undo her own design by making him too moony to maraud on his beloved's behalf. And your female, having gotten what she wanted from her tryst, she needs some extra encouragement to stick around and wait for the boob. I mean, she could go out and get another guy while he's hunting buffalo, sexy and available as she is. But no, she's got this drug in her that makes her want him and only him. And so we have, if not equality, a kind of balance.