Aim For Once a Week (That's Doable, Right?) Believe it or not, couples who have sex just once a week are happiest, according to a long-term study of over 30,000 people. Another survey of sex researchers by the Sexual Health and Relationships Lab at the University of Toronto found that the optimum length for sex is a mere 7-13 minutes. Even the most fried parents can manage seven minutes a week. Image Source: Unsplash/Becca Tapert