The key factors in maintaining a satisfying sex life in a long-term relationship are foreplay and telling your partner you love them.
The US team behind the findings studied common romantic and sexual behaviors to find why some couples are happier with sex than others.
The study which focused on heterosexual couples found, those who said "I love you" and were intimate by cuddling, kissing and laughing together during sex were more satisfied.
For some couples, keeping sex varied by trying new positions and acting out fantasies also helped, as well as setting the mood with lighting, music, or sending teasing texts earlier in the day.
The study examined more than 38,747 married or cohabiting couples in the US who had been with their partner for at least three years.
Participants were asked to rate how satisfied they were with the sex during the first six months of their relationships, and to compare that to how they felt at the time of the study.
Eighty three percent of people said they were sexually satisfied in the first six months of their relationship. However, 41% women and 27% of men, said they were currently dissatisfied.
Dr. David Frederick, Assistant professor of psychology at Chapman University and lead author of the study said, "Almost half of satisfied and dissatisfied couples read sexual self-help books and magazine articles, but what set sexually satisfied couples apart was that they actually tried some of the ideas."