MELBOURNE – There is a number sitting somewhere between desire and routine, and scientists have been trying to pin it down for years. Just after National Orgasm Day, a new study from the University of Melbourne has given couples something to sit with: young adults who describe themselves as deeply in love report having sex an average of 3.5 times per week. Not twice. Not five times. Three and a half.
The study, published in Current Sexual Health Reports, was led by researcher Adam Bode, who analyzed data from the Romantic Love Survey 2022, the largest publicly available dataset of people experiencing romantic love. More than 1,500 young adults from 33 countries participated, reporting on the depth of their feelings and the frequency of their physical intimacy. The 3.5 times per week figure that emerged sat well above the once-per-week average associated with married couples in the general population, and that gap tells a quiet, complicated story about what the early stages of love do to people.
What Bode did not find is at least as interesting. The intensity of a person’s love, how consuming the thoughts, how profound the commitment, how acute the longing, had no meaningful bearing on how often that person was having sex. Being deeply in love did not predict higher frequency. Being in the early stage of romantic love did. The experience of love is not its arithmetic.
This is where the science becomes genuinely seductive.
A foundational study from Amy Muise, then a postdoctoral fellow at the University of Toronto Mississauga, tracked more than 30,000 Americans over four decades and identified something that has since become one of the most-cited findings in relationship science: couples who have sex once a week are the happiest. Not those who have it more often. Not less. Once a week appears to be the frequency at which people feel their intimate connection is maintained without tipping into performance or pressure. Beyond that threshold, happiness did not increase. The intimacy still mattered; only the arithmetic stopped. NBC News covered the research when it first emerged, noting the pattern held regardless of gender, age, or relationship duration.
“Our findings suggest that it’s important to maintain an intimate connection with your partner,” Muise said, “but you don’t need to have sex every day.” Single people showed no association between sexual frequency and wellbeing, suggesting the benefit is specific to committed relationships rather than the act in isolation.
So where does that leave the 3.5? Bode’s research offers a plausible explanation: early-stage romantic love produces what psychologists call limerence, a state of near-obsessive emotional intensity that floods daily life with urgency. Bodies respond. But his most counterintuitive finding, that the depth of that obsession has no predictive power over frequency, suggests the link between love and sex is less direct than most people assume. People in early love have more sex because they are in the early stage, not necessarily because they are more devoted than someone equally committed but eight years into a partnership with a Tuesday commute.
An analysis of the General Social Survey covering more than 26,000 American adults from 1989 to 2014, published in Archives of Sexual Behavior by researchers at Florida Atlantic University, found that Americans are having sex less frequently than a generation ago. The married and cohabiting population that averaged 73 sexual encounters per year in 1990 was down to 55 by 2014. Partnered people declined the most sharply. The trend predates smartphones by a decade, which makes it less a story of crisis and more a story of slow cultural drift, more working hours, more screens at bedtime, more exhaustion spread across every demographic.
The research in this area does not suggest there is a number that works for every couple. What it consistently finds is that the right frequency is the one that sustains connection rather than depleting it. Obligation produces different chemistry than desire. Studies on sexual satisfaction consistently find that quality predicts relationship happiness more reliably than frequency, a finding that might seem obvious until one considers how often couples treat the two as interchangeable.
For the persistent gap in orgasm frequency between men and women in heterosexual relationships, sheer frequency may be almost beside the point. Research has shown that women achieve orgasm approximately 65 percent of the time during heterosexual encounters, compared to 95 percent for men. That gap does not narrow as the sex becomes more frequent; it narrows when communication does.
On a day designed to celebrate the orgasm as a biological event with genuine health consequences, the Melbourne study most usefully contributes not a quota to hit but a reminder that the 3.5 reflects a neurological state. It is a description of where people are in early love, not a prescription for where they should aim. The task for long-term couples is different, and more human: not to match the number but to preserve what it represents. That desire, like any living thing, needs tending.
As for whether the frequency produces the love or the love produces the frequency, Bode’s research, honest in its limits, declines to say. Both remain open. That ambiguity may be the most honest thing about it.
