Above that, the association with wellbeing flattens completely.
Three studies covering more than 30,000 people found the expected result up to a point: couples having sex more often reported greater wellbeing. The curve then stops. Beyond roughly once a week there was no additional association — couples having sex daily were no happier than those having it weekly.
A separate experiment tested the direction of causation by asking couples to double their frequency. Their mood and enjoyment went slightly down. The researchers concluded that frequency mostly reflects wellbeing rather than producing it, and that being told to have more sex makes it feel like an assignment.
