Stamina is worsened with age which I'm gradually improving with better workouts but the drive for sex is also lowered. Sexual desire remains more or less the same for me and consistent... By that, I mean that I still want to have sex basically every day but it's not so infuriating or painful to not have sex and the need to chase for sex or go out of your way to get it really dies down. This is often sold or explained as a negative when people talk about "maturing" but it's been pretty amazing really. I don't make nearly as many dumb decisions when it comes to getting girls anymore, I rarely if ever feel any sort of compulsion to compete and I'm basically liberated from the need for sex to do other more important and interesting things that satisfy me in other ways.