We surveyed 411 adults, and all respondents indicated that they currently have at least one FWB [1]. The respondents' ages ranged from 18 to 65 years old, and the majority (86%) were heterosexual. Each respondent was asked about their expectations for the future FWB relationship, which could mean maintaining the FWB relationship for a long time, becoming an intimate partner, becoming just a regular friend, or having no relationship at all.

It has been proven that men and women have very different responses to this issue. The vast majority of women (69%) want their relationship to change, while the majority of men (60%) prefer to maintain the status quo. In other words, women are more likely to view their sexual partner as a temporary state, while men are more likely to consider their sexual partner as an ultimate state.

What aspects do women expect their partners to change? (Compared to men, women) are more likely to expect them to develop into romantic partners (43% vs. 24%). Women also expect them to eventually return to being just ordinary friends (20% vs. 10%) more than men do.

The sexual behavior between friends and lovers shows significant differences in many aspects.

In a conference report of the Society for the Scientific Study of Sexuality, I discussed the results of a survey involving approximately 1,100 adults. These respondents currently have a casual partner (26%) or an intimate partner (74%) [2]. The average age of the participants was 29 years old, and the majority identified themselves as heterosexual (74%).

Everyone was asked to indicate whether they had engaged in various specific sexual activities with their partners, ranging from ordinary sexual acts to peculiar sexual behaviors.

When comparing different types of relationships, one difference observed is that partners in romantic relationships are more likely to kiss than casual sex partners, although this difference is quite small. However, the differences observed in sexual preferences and polyamorous activities are much greater.

The possibility of a threesome between sexual partners (FBW) is approximately twice that of ordinary couples, and the likelihood of sexual partners attempting to engage in bondage is 50% higher. Why is this so? This might be because in relationships with a higher level of sexual communication, BDSM desires are more likely to be shared and acted upon, such as in romantic relationships (in fact, in some of my other studies, I found that romantic partners are more likely to communicate their sexual desires than sexual partners). Nevertheless, in relationships where sexual partners (I have always found that such relationships are mostly non-monogamous) do not have much pressure to maintain sexual exclusivity, the desire for polyamorous sexual behavior may be more likely to be acted upon.

Another difference between extramarital affairs partners (FWBs) and sexual relationships with lovers lies in the practice of practicing safe sex. In a 2014 paper we published, using a sample of 376 people who currently have extramarital affairs partners or lovers, we found that FWBs reported using condoms more frequently than lovers [3].

The long-term outcome of FWB is mixed; most cases seem to disappear within one year.

In my recent research on sexual partnership relationships (FWB), we conducted a one-year longitudinal study on 192 individuals who claimed to have such relationships [4]. We surveyed them at two different time points, with an interval of approximately one year. The majority of the sample was heterosexual (72%), with an average age of 30.

In the first survey, we asked the participants about their expectations for their relationship in the future. They were also asked about their satisfaction with the relationship, as well as the degree of communication regarding the rules and boundaries of the relationship. In the second survey, we asked whether the nature of their relationship remained the same or had changed - if it had changed, please explain the reasons.

We found that certain relationship outcomes were more likely to occur than others. One year later, 26% of the people remained as casual partners, 15% had become romantic partners, 28% had resumed normal friendships, and 31% stated that they had no connection with their previous casual partners. In other words, the vast majority of casual partners broke up within one year. However, most of the participants still maintained at least some form of relationship with each other, and approximately one-third of them cut off all contact.

The effectiveness of FWB depends on your expectations and communication skills.

In the longitudinal study I mentioned, we found that some relationship goals seemed to be more achievable than others. Specifically, those who wanted to restore ordinary friendships seemed to be the most successful: among the first group of people who desired to restore ordinary friendships, 59% achieved this goal on the second attempt.

Those who aim to maintain a FWB relationship for a long time have a slightly lower success rate. Among those who expressed this desire for the first time, 40% reported that they remained in a FWB relationship on the second attempt. In contrast, those who aim to transform into a romantic partner have the lowest success rate. Only 15% of them achieved this goal after one year.

Furthermore, among those participants who indicated maintaining a certain type of relationship (whether sexual or non-sexual) with their partners over an extended period of time, they reported having more communication about establishing basic rules at the first time point. Those who communicated less were more likely to report at the second time point that there was no relationship between them.

We also found a similar pattern of results regarding the satisfaction with friendships: those who were initially satisfied with their friendships were more likely to maintain a certain relationship over the long term.

These findings suggest that the true key to the success of FWB seems to be highly related to matching expectations, good communication, and a strong friendship.

Summary

Based on the number of studies I have conducted, I can say quite a lot about FWB. However, I don't have the time to cover all the details in this article. But I hope this will allow you to understand some of the key points I have learned through all these efforts.

I initially embarked on this research because many of the students in my human sexuality class asked me how to make a sexual relationship successful. At that time, I didn't have a good answer because I had no data to refer to - but now I do!