It's a superficial historical construct that "sex" is its own subject akin to "fiction." The separation of sex from the rest of our personalities has caused tremendous repression and a splitting apart of the self between the waking, or non-sexual, socially appropriate self and the sexual self, the hidden self, the taboo self.
Carl Jung, the pioneer of the idea of archetypes in the human experience, conceptualized the idea of our buried fears, anxieties, taboo thoughts and feelings, our "darker selves" as, literally, our shadows. Carl Jung realized that this shadowy part of ourselves must be acknowledged and somehow integrated into our adult personalities in order for us to become truly whole.
Please read more about this here: http://webspace.ship.edu/cgboer/jung.html. For a list of books by Jung, please follow this link: http://www.bestwebbuys.com/Carl_Gustav_Jung-mcid_3135042.html?isrc=b-authorsearch.
What is the benefit of incorporating our sexuality into ourselves? As Jung describes it, the life cycle will not come to a satisfying point in old age if one has not made peace with one's choices and decisions. Being older is, in a healthy person, a period of reflection and coming to terms with one's life. Knowing one's self at the deepest level would make for a more profound experience in later life, when taking stock is in direct proportion to feeling, knowing and accepting what one's life has meant and what one has learned.
By cutting sexuality off from the rest of ourselves, we fool ourselves into thinking that we have two of us living simultaneously in the same body; that we make decisions without any of our sexual nature involved and that sex is indeed completely separate from love, from rational thought and from being considered an adult.
Women are the first to blame men for this division, complaining endlessly that men can treat sex as a romp, a sort of entertainment with no strings, love or emotion attached.