Love is one of the most profound emotions known to human beings. For some, romantic relationships are the most meaningful element in their lives, providing a source of fulfillment outside of ourselves.
At least for humans, this most basic of acts is anything but basic. As the pioneering sex researcher Alfred Kinsey put it, the only universal in human sexuality is variability itself. Within the universe of intimacy and pleasure that sex affords, however, there's a lot of room for error.
For a topic as subjective as morality, people sure have strong beliefs about what's right and wrong. Yet even though morals can vary from person to person and culture to culture, many are practically universal, as they result from basic human emotions.