There r a whole lot of nonvegetarians who dont mind killing and eating (am one among them).And others who cant stand killing for eating... from a moralistic point of view may be killing is wrong... but then all of us exist. for people who cant feel kindness being non vegetrian is okay but for others its not... so is sex..if you have ifs and buts then yu should be in a monogamous relationship....otherwise its your choice...we kant keep comparing ourselves with animals like most of us do... we have evolved form them and whether we like it or not we will evolve further, by comparing ourselves with animals we will be only acting against evolution and hence nature. any ways whoever want to have heavenly sex let them have and whoever wants a steady relationship let them have too...we all get what we want.