Somatic vs. empathetic pleasure
Men’s machinery isn’t all that hard to operate. If climax were the goal, well, most healthy adult males can have as much of that as they want. They don’t even need a partner. But there can be something lacking in that experience, a missing ingredient.
While direct, somatic, bodily pleasure comes easy to them, there’s an empathetic component — shared experience or sharing in someone else’s experience — that men hunger for.
In short, men are seeking connection. It’s what makes the physical stimulation in sex a complete experience.
As for women’s machinery, we used to think of it as complicated or mysterious. Now we know it isn’t. It certainly is different from men’s though.
Women typically have no shortage of available and willing partners — if simply having a partner was all that was needed — but again there can be something lacking in the experience, often profoundly so. Women often find themselves producing more pleasurable sensation in their partner’s body than what they’re experiencing in their own.
So they have easy access to as much empathetic pleasure as they could ever want, and can easily end up defaulting to that, with mostly vicarious enjoyment in sex, while getting short-changed on the vital nutrient of direct, somatic, bodily pleasure.