Sex is a big part of most romances, whether a marriage or a more experimental union. A recent survey of Europeans shows that people in the most sexually liberated partnerships aren’t having the best time. Monogamous couples reported that they were the most sexually satisfied of all the groups in a large, representative survey conducted in March 2017.

Among the 1,885 people who said they were in monogamous relationships, 82% reported that they were broadly satisfied with their sex life. That compared to 80% of people in a marriage, civil union or other legal partnership, while 71% of people in open or polyamorous relationships said they were fulfilled.

The survey, conducted by Dalia, a Berlin-based research company, included over 11,000 people from the 28 countries in the European Union aged 14-65, though for the purposes of reporting they then excluded those aged under 18.

The findings echo US research that showed that people with young kids had the most sex of all Americans. People who live together (as couples with children often do) have readier access to sex than those in relationships who don’t live together. The EU survey only found 275 people, or 2.5% of the total, who said they were in open relationships.

Age and gender also affect sex-life satisfaction. Men overall reported a slight increase in satisfaction as age increased, while women’s satisfaction remained stable. For both genders, the highest peak was between the ages of 25 and 30. And though not every country in the EU provided enough respondents to produce a statistically significant finding, some that did showed marked differences. Spain proved to be the most sexually satisfied country with 41% of people saying they were “very satisfied” with their sex lives, while in Germany that number was 38%. In Poland only 23% said they were ”very satisfied,” compared to 28% in Italy and 29% in both the UK and France.

Opening up a relationship can be about more than sex. Advocates talk (paywall) about the deep trust forged by letting one’s partner have other relationships, and the intellectual stimulation and support gained from multiple romantic connections. But the surveys indicate that multiple partners may well not trump one really great one in the bedroom department.