Young women tend to have little problem with sexual delights as long as their partner is not a dud or a selfish jerk.
Middle-aged women (40-65) tend to be more readily orgasmic. It is hormonal, in part. Women in good health remain capable of sexual delight and orgasm until death, but the climaxes are not the same. Still satisfying, but not the screaming or moaning ones of a 35 year-old.
Healthy men over 60 tend to have a decline in sex drive and performance, but not in sexual/romantic interest. It's complicated. It is age, hormonal issues, and other things. Men are, biologically, more excited by fertile females of course, but bonding with the wife is important. She's right there, and willing. With age (say, over 70 or 75) things are not what they were at 40 but men are still capable of, and needful of, romantic and sexual pleasure.
It is a component of life happiness.
Yes, you can have better sex in midlife and in the years beyond. If sustaining intimacy is becoming more difficult, there are many approaches that can help.