For the study , published online this week in The Journal of Sex Research, researchers looked at data that had originally been collected in 2006. They focused on 38,747 heterosexual men and women who were in a relationship for at least three years. Over 80% of the participants reported that they were happy with their sex lives in the first six months of the relationship. But only 55% of women and 43% of men said they were satisfied with their current sex lives.What are the secrets of those who were still satisfied? Obviously relationships (and why they last, and what makes them 'good' or 'healthy') are complex things, but here are the major trends the study's authors were able to tease out:Unsurprisingly, participants who said they were more satisfied with their sex lives almost always reported having had an orgasm in the last month (98% of men and 78% of women). But, crucially, they also were more likely to say that their partners had orgasms during that time as well.Both male and female participants with more satisfying bedroom lives were more likely to report that their last sexual encounter lasted a long time — at least 30 minutes. But this was only true for about half of the satisfied participants (compared to about a quarter of unsatisfied people) so it's not exactly the norm, it's just a more frequent option.Never underestimate the power of putting your heart on the line when things are getting physical.The majority of both men and women in the study reported saying that they had the same (or greater) level of emotional closeness with their partner now than they had during their first six months together. Satisfied participants were also more likely to say "I love you" and to laugh about something funny that happened during sex — all little things that build into the overall feeling of intimacy.