hey i know why its in our instinct to want to have a few partners before we settle down. "With dopamine as the driving force, biology has designed you to engage in fertilization behavior to make more babies, and urges you to move on to new partners to create greater genetic variety among your offspring. so there u go, we have no one to blame but our genetic makup and our desire to spread it as much as possible. u just think about rats in a alley way. they need to have that instinct to so that there are less brothers and sister having sex, preventing retarded offspring. we are closest in genitic makup to rats thus why lab rats r used frequently.