Commenting on my post about how getting together with friends can provide a nice oxytocin boost that makes a woman happier in her marriage too, Dave said:

Over the years I have heard the importance of communicating, sharing non-sexual intimacy, supporting each other, etc., etc., but have rarely heard women openly say that sex is what bonds them to men. How about the more experienced couples (I don't want to say "older") - would most women who have been married 10, 20 years or more agree that sex is still the bonding element ? I believe it is, but do they ?

I think "ideally" is the operative word. Unfortunately, when it comes to sex and orgasm, the situation for women is far from ideal.

Orgasm can be problematic for women for several reasons. While this doesn't hold true for everyone, and I think our culture might be changing, many times:

Women are taught that sex is dirty or bad.

Women are not taught to get in touch with our bodies to learn what feels good, and what good sex should feel like.

Women are not taught to ask for what we want, in bed or out of it.

Pornography, as well as our soft-porn entertainment industry, portrays men and women as always sexually ready and available. Men can be really surprised, frustrated and bored  when a woman needs a lot of foreplay. I mean, we may be talking 20 or 30 minutes. How many men are, ahem, up for that?

Men get angry, annoyed, put off or insecure if women ask them to change what they're doing during sex, because  it makes them feel criticized.

Neither men nor women are taught anything about making love. We blunder through it at first, and often pick up bad habits.

Once a man and a woman become regular sex partners, it's not as *exciting*. So, the woman may actually need more foreplay or to be approached more slowly, while the man may feel he doesn't have to seduce her any longer.

As a man gets older, his erections may be less strong or less reliable. Our culture unfortunately expects men to be always ready sexually, so they feel shame if they don't get an erection right away. Instead of focusing on his partner and letting it happen or not, the man starts to focus more and more on his penis, making sex less and less pleasing for his partner.

So, a couple may start off with some bad sexual habits: He rushes things, she doesn't demand that he slow down, etc. Then,  after 10 or 15 years, when his testosterone dies down, sex begins to seem kind of pointless to her and she puts him off more and more.

They hopefully still will bond through sleeping together, hugging and other less sexual kinds of touching. We hear about couples who have sex into their 70s and 80s. I suspect they're the lucky minority.