On one level, sex is just another hormone-driven bodily function designed to perpetuate the species. On another, it's a pleasurable activity. It's also an activity that can help cement the bonds between two people.
Sexual health refers to a state of well-being that lets a man fully participate in and enjoy sexual activity. A range of physical, psychological, interpersonal, and social factors influence a man's sexual health.
Optimal male sexual health includes sexual desire (libido) and the ability to get and sustain an erection (erectile function). Although physiology can affect both the desire for sex and the ability to have sex, mental health and emotional factors also play important roles.