We tend to assume that old people have no sex drives, and that our grandparents last enjoyed nookie way back in the days when people still called it "nookie," but that simply isn't true. Even if some younger people have more frequent sex, studies say that older people are getting more enjoyment out of the sex they do have. Practice, and knowing your own body, mean a lot more than having tight youthful abs.
And romantic prospects are looking especially rosy for older bachelors. Men tend to die younger than women, so a silver-haired, single gentleman has his pick of lonesome widows. The aging male physique can also improve in surprising ways. The skin gets less oily (so no more bacne), the thinning of body hair can make him less ape-like, and the inevitable loosening of the ligaments downstairs can even make the penis appear larger.
So please don't let pop culture tell you that your lonely early 20s are a waste of your precious sexual prime. And definitely don't let a bunch of old sitcoms and standup routines tell you that sex dies with marriage, as if it's all downhill from there. It totally isn't.