If you are thinking too much about sex (again how much is more varies), that is a sign of declining ability. Desperate to flood your androgen receptors in the brain with the flow of androgen (that may be diminished with multiple factors), one have to indulge in too much sexual carving. This again will desensetize the receptors and demand more the cycle continues hastening andropause. Bottom line, sex like alcohol is best is used in moderate. For evidence try having sex on the week filled with sexual thoughts and next week with relatively reduced thoughts playing and you will feel the difference ( from an amature experts point of view)