On Dating ...After a Certain Age

The body is not the same -- the exercise regimen to gain that "six pack" is no longer there. Even the day-to-day habits admit of little possibility for growth, or, horror of horrors, change. And yet the desire for human companionship and love continues without stopping --- well past 50, or 60, or beyond. Why is that?

Why are we wired this way? Is there never an abatement of the demands put on our psyche? Are we always going to want to risk the embarrassment of rejection? And for what? A kiss in the dark, a friendly hand caressing us; a warm hug to reassure us?
Is it worth it?