Sexuality expresses itself in many different ways in nature. With human beings, it isn't just monogamy or polygamy that is natural. However, we may be able to simplify the plethora of categories to measures of sex drive and socio-emotional need. These things, as most things are, are most likely contingent to circumstance and can vary fluidly throughout one's experience. Also, something that most won't admit, in our current socio-economic environment, the influence of power dynamics is prevalent.