A new comparative study into sexual activity among married couples finds that those in South Korea report higher rates of sexual inactivity than their counterparts in the United States, even though both groups show similar links between age, personal motivation and intimacy. The work, conducted by researchers from Yonsei University, and published in The Journal of Sexual Medicine, sheds light on how cultural and structural differences shape physical closeness in long-term relationships.
Physical intimacy is widely regarded as a central component of marital well-being, with regular sexual activity commonly associated with higher relationship satisfaction and overall health. Conversely, a lack of sexual activity is often linked to emotional distance and lower life satisfaction.
Global trends show rising marital sexual inactivity, with prior estimates suggesting about 15.6 per cent of married couples in the United States report no sexual activity, while rates in East Asian countries have been placed between 42 and 55 per cent.
Despite these figures, cross-national comparative research has been limited by inconsistent timeframes and methodological differences, including the tendency to combine married and unmarried individuals in analyses. The Yonsei University study aimed to address these gaps by using identical survey methods and a uniform definition of sexual inactivity, focusing specifically on married adults in South Korea and the United States.
The researchers, Hyoungbin Moon and Young-Hoon Kim, contrasted two national contexts that differ notably in working hours, gender norms and social expectations. The United States is characterised by comparatively egalitarian sexual norms and flexible work patterns, while South Korea is known for longer working hours and more traditional norms surrounding gender and sexuality.
They hypothesised that these cultural and structural differences could influence couples’ available time and relationship dynamics. In addition to demographic factors such as age, gender, education and family income, the study also evaluated psychological variables including daily communication time and emotion suppression, the tendency to hide one’s feelings.
Two regulatory orientations were assessed: promotion focus, a growth-oriented mindset seeking positive outcomes, and prevention focus, which emphasises avoiding losses and fulfilling obligations.
Data were drawn from anonymous online surveys conducted in 2021 and 2022, with final analyses limited to married adults aged 19 and over who completed attention checks. The analytic samples ranged from 3,364 to 5,270 participants depending on the variables tested, with responses provided by individuals rather than couples.
Sexual inactivity was measured by a single direct question on how many times per month the respondent had intercourse with their spouse. This design means the data reflect one partner’s perspective within the marriage.
The study found that the prevalence of sexual inactivity rose with age in both countries, but was consistently higher among Korean participants across all age groups.
A promotion focus, reflecting a growth-minded approach, was associated with lower rates of sexual inactivity in both the United States and South Korea. By contrast, a prevention focus did not significantly predict sexual inactivity in either nation.
In both contexts, greater daily communication time correlated with lower sexual inactivity, suggesting that more frequent conversation supports sustained intimacy. The association appeared stronger in South Korea, where long working hours may limit opportunities for connection, making any shared time particularly influential.
Economic resources interacted with national context as well: income showed a stronger negative association with sexual inactivity in the United States than in South Korea, implying that higher earnings may be more closely linked to relational well-being and intimacy in the American setting.
Several findings appeared unique to the South Korean sample. In this group, women, individuals with postgraduate degrees, and those who frequently suppressed their emotions reported higher rates of sexual inactivity. However, the researchers cautioned that the statistical interaction comparing emotion suppression between the two countries was not statistically significant, so the apparent cross-country difference should be interpreted with caution.
The researchers acknowledged several caveats. The cross-sectional design cannot establish causality, so it is unclear whether reduced communication leads to sexual inactivity or vice versa. Self-reported data may be subject to memory bias or social desirability, and the findings are limited to two countries, limiting generalisability to other cultural contexts.
The study, titled Prevalence and correlates of sexual inactivity among married couples, was authored by Hyoungbin Moon and Young-Hoon Kim. It highlights the complex interplay of demographic and psychological factors in marital intimacy, and raises questions about how work life, gender norms and communication shape private relationships across different societies.
