Complex sentence: Sexual activity is a vital principle of human living that connects the desire, energy and pleasure of the body to a knowledge of human intimacy, for the sake of erotic love, intimate friendship, human mating and procreation.
Split into simpler sentences: Sexual activity is a vital principle of human living that connects the desires, pleasures, and energy of the body with a knowledge of human intimacy. This results in erotic love, intimate friendship, human mating and procreation.