New research suggests that if you want to maintain your relationship, having sex could give you and your partner a short term boost of sexual satisfaction which also has a longer-lasting effect on your relationship.

Carried out by a team from Florida State University, the researchers theorized that although sex is essential for reproduction, and of course also pleasurable, it is also has an additional purpose of bonding couples together.

As most adults report having sex with their partners every few days, not every day, the team set out to look at the effect that sex could have on a short-term boost to sexual satisfaction, and how it could create and sustain a bond in between these sexual experiences.

They also wanted to see if sex could also have a more long-term effect on enhancing a couple's relationship satisfaction.

To test their hypothesis, the team looked at data from two independent, longitudinal studies, one with 96 newlywed couples and another with 118 newlywed couples.

The couples had all completed at least three consecutive days of a 14-day daily diary as part of a larger study, in which every night before going to bed they were asked to report on whether they had sex with their partner that day.

Whether they had had sex or not, they were also asked to rate how satisfied they were with their sex life that day and how satisfied they were with their partner, their relationship, and their marriage also on that day.

The couples also completed three measures of marriage quality at the beginning of the study and again at a follow-up session about 4 to 6 months later.

The diary entries showed that, on average, participants reported having sex on 4 of the 14 days of the study, although answers did vary considerably among couples.

However, regardless of how often the couples were having sex, the team found that sex on a given day was linked with sexual satisfaction that same day, and the next day, and even two days later, giving the participants a 48-hour "afterglow" after just one single act of sex.

The sexual afterglow was also found among both male and female participants and among participants of all ages, and also held true even after personality traits, length of relationship and other factors were taken into account.

It was also linked with relationship quality over time and not just in the short term.

Although the team found that overall, all participants' marital satisfaction declined between the beginning of the study and the follow-up session 4 to 6 months later, those who reported a stronger sexual afterglow 48 hours after sex also reported higher initial marital satisfaction and less steep declines in satisfaction across the first 4 to 6 months of marriage.

As the same association was found in both the independent studies, the team believe that together the findings provide strong evidence to support the theory that sex and sexual satisfaction are linked with relationship quality over time and function to keep couples bonded together.

The results can be found online published in Psychological Science, a journal of the Association for Psychological Science.