When you get older, nearing the 30s, your natural test production decrease. It's natural, normal. Hence your stamina, and will to perform physical tasks decreasing too. It is a natural process that is suposed to make you focus on family and kids, not on "lifting weights" and "flirting and banging for one night every single girl you can like a teen". Just because you can doenst mean you should. It s also often because you cant do anything else... because you dont have what it takes coming from a dysfunctional family yourself maybe.
Hormones motivate these impulses.There s a need for brains at some to take control over the impulses and create good things with them. Only mature, spiritual people can.
But fact is as an inteligent animal you re suposed to conquer your beloved one during your youth showing off your physical prowess and smarts, then settle with one and only one, take care of kids and that's about it. Wanting to stay on the top forever, wanting to be young, dominant, forever, is impossible and a seriously flawed understanding of our human lives. Also the dominance you can excerce on others is replaced by your dominance over your family -well, for some men-. As an intelligent animal your physical beauty and strenght, and your intelligence -ability to adapt to insure your survival- are nothing, can destroy you and others if you dont use them properly using spirituality, Faith.
Among all models a man can follow, the christian family man one is the best, simply because it is also the only one that insure the survival of the specie. It'S the right track, the right middle ground. Look at all of those who didnt follow this model, how they end, or look at those who pretended to follow it, but didnt, only pretended to. They all fail in the end. One spermatozoid reach the egg. Many are called, but few are chosen. Life is binary. When you re old you think you can do everything, until you realize how complex life truly is and how hard it is to cultivate and preserve it.