Men and women are basically entirely different species. A girl may say she hangs with the guys more than her girlfriends or a guy may in fact be more sensitive than the average, however, they are still from completely different and separate planets. One of the biggest relationship deal-breakers is cheating. Whether it was a onetime fling or a long-term relationship, many persons find it very difficult to forgive, and nearly impossible to forget an act of infidelity. So who in a relationship is more selfish, the girl or the guy?