Love is based on a need for humans to form "pair-bonds". The evolutionary purpose of our human sexuality is to strengthen this bond. Through many different techniques humans naturally select an individual to pair with. The different sexes have different reasons and or motivations for creating pairs. Love being created through interaction and established through relational, social or psychological methods are a derivative to compromising ones reasons or motivations for creating a pair. This is a habit that we have developed over time. Love is a result of a natural match between ones love interest and their expectations therefore making it a chemical mechanism. Humans evolve because of natural selection. Just as evolution is natural so is love and it works as the fuel for evolution. Love combines two different bodies of life and makes them as one progressing the overall quality of life. .
Our organs including the human mind are designed to transmit genes to the next generation. For example we naturally feel hunger because it was successful in keeping our ancestors alive to rear us. We feel lust because it is what led us to being created. Today this lust is viewed as a means merely to become intimate with a partner but it is really a reaction to the need to mate to reproduce. Our ancestors did not have the same temptations that alter ones reasons for sex. This is evident in the dramatic change in the worlds open acceptance to a sexually active society. An issue that at one point was not addressed but assumed because of reproduction is now used a promotional tool for everything from bubble gum to music. Confusion created because of ones conflict between heir own values and beliefs and those of the environment is natural. Humans learn not only from what they have genetically accumulated but also through experience. Because of temptation people have discovered a way to deal with temporary gratification therefore completely redirecting the purpose of lust from an evolutionary standpoint.