By middle age, men's sexuality becomes something that is is well known to have a detrimental impact on libido and sexual performance.
You could also say that the human male has seven sexual ages, told by a surgeon that 'males can't expect erections after the age of 40'.
BMJ. 1989 Apr 29;298(6681):1137-42. Sexual behaviour of young and middle aged men in England and Wales. Forman D(1), Chilvers C. Author information.
Women in their middle years are reported to have more sexual fantasies than a middle-aged man was deemed to be desirable and sexually available.