It is a very popular belief that women gain weight on their breasts and hips once they start making love. However, this is an absolute myth. There is no physiological reason why the breasts or hips should become enlarged or disfigured after a woman starts having sex. There is no way that ejaculated semen can get digested and assimilated in the bloodstream. And, in any case, 2–3 ml of semen (average ejaculation)contains only about 15 calories! Some studies do suggest that people gain weight after marriage. But even these unconfirmed reports say that this is true for both women as well as men. And the weight gain has nothing to do with sex for either gender. It's often the comfort of being in a relationship and the associated sense of security that make people gain weight. Studies also show that people in relationships are likely to eat more than single people. If you want to avoid gaining weight after marriage, exercise regularly and maintain a healthy diet. Source: timesofindia.indiatimes.com