What motivates people to have sex? Amy Muise and her colleagues at the University of Toronto say there are two main reasons we get it on: approach goals and avoidance goals. A person who has sex for "approach goals" is motivated by positive outcomes, such as feeling closer to a partner or physical pleasure. In contrast, a person who has sex for "avoidance goals" is focused on avoiding negative outcomes, such as disappointing a partner or preventing a fight. Approach and avoidance theories of sexual motivation are not new. But for the first time, researchers looked at how a person's sexual goals impact the quality of the relationship and the level of sexual satisfaction of their partner. This was demonstrated in three studies recently published in the journal Personality and Social Psychology Bulletin. In short: Researchers found that people's goal's for sex matter. It changes the sexual experience.