1. Several psychology studies have documented a positive association between sexual frequency and romantic relationship satisfaction. Having more frequent sex is also associated with greater overall well-being. (Cheng and Smyth, 2015; Laumann, Gagnon, Michael, and Michaels, 1994, Byers, 2005, Blanchflower and Oswald, 2004).
2. Human beings enjoy having sex. In fact, in a study where people rated how happy they felt after undertaking a range of daily activities, sex was rated as the number one happiness inducing activity (Kahneman and Krueger, 2006).
3. Blanchflower and Oswald's (2004) study found that the more sex people reported, the happier they felt. Average sexual frequencies vary, but in their book The Normal Bar (2013), Northrup, Schwartz and Witte suggest that the magical number for happy couples is three to four times per week.
4. However, that figure is very much at odds with data from the most recent NATSAL (2013) study which estimates that the average sexual frequency in the UK is now less than five times a month.
5. For couples with busy lives, work responsibilities, and children to care for, 'getting it on' three or four times a week is a daunting prospect. The ''good enough sex'' model acknowledges that it is important for couples to engage in sexual intimacy to maintain satisfying romantic relationships, but also to hold realistic expectations about their sex life (McCarthy and Metz, 2008; Metz and McCarthy, 2007).
6. Forcing yourselves to have more sex doesn't seem to work either. In a recent study in which couples were asked to double their sexual frequency, there was no measurable increase in well-being compared to those in a control group who maintained their current frequency (Loewenstein, Krishnamurti, Kopsic, and McDonald, 2015).
7. The authors of the study concluded that directing couples to increase their sexual frequency removed their intrinsic motivation to engage in sex and that made having sex a chore rather than a pleasure.
8. There is a surprising lack of consensus on frequency given that 'how often couples have sex' is the most commonly assessed aspect of sexual behaviour within sex research literature (Cohen and Byers, 2013; Schwartz and Young, 2009; Scott-Sheldon, Kalichman and Carey, 2010).
9. In the most recent attempt to clarify the relationship between sexual frequency and happiness, Amy Muise, Ulrich Schimmack, and Emily Impett at the Department of Psychology, University of Toronto analysed two existing studies (N = 30,645) which contained existing data on sexual frequency and levels of wellbeing. They also carried out a third study of their own to confirm their findings. Essentially, they found that having sex once a week is associated with enhanced well being and greater relationship satisfaction, but for people in relationships, sexual frequencies of more than once a week have no additional benefit. Phew. That's all of us off the hook.
10. The authors admit that they cannot make 'causal claims' about the relationship between sexual frequency and relationship satisfaction. Of course they can't. Although sex obviously makes couples happy, it is equally and obviously true that happy couples tend to have more sex. The authors conclude that sex is probably a bit like money; only too little is bad for us.