Sexually fantasizing about your partner could help motivate you to engage in relationship-promoting activities, according to researchers at the Interdisciplinary Center Herzliya, Israel.

These activities may be both sexual and non-sexual in nature — this suggested the overall relationship received a boost in appeal, not just sexual desire for the partner.

The study titled "What Fantasies Can Do to Your Relationship: The Effects of Sexual Fantasies on Couple Interactions" was published in the Personality and Social Psychology Bulletin on Aug. 18.

"Research addressing the underlying functions of sexual fantasies has mainly focused on variables associated with frequency and content of fantasies," the authors stated in the paper. "Relatively less is known about how sexual fantasizing affects the relationship."

The team conducted four studies to understand how relationships are affected by dyadic fantasies i.e. fantasizing about one’s partner. Fantasizing about someone who is not a partner is referred to as an extradyadic fantasy.

For the first two studies, the team recruited participants who were romantically involved with someone. They were instructed to sexually fantasize about either their partner or someone else and also describe the content of their fantasy.

Following this, they were asked to rate their desire to engage in relationship-promoting activities (both sexual and other non-sexual) with their partner. Those in the dyadic fantasy condition reported a greater desire to engage in the aforementioned activities compared to their counterparts.

The third and fourth studies helped the researchers understand why this desire was improved. By filling out a diary on a daily basis, partners were asked to record their fantasies and relationship interactions over the course of three weeks and six weeks respectively.

This included how often they sexually fantasized about their partner, as well as positive and negative perceptions they had about their relationship every day — for example, finding the relationship to be very valuable one day or having doubts about one's compatibility with their partner on another day.

Fantasizing about a partner was found to enhance their appeal, contributing to a cycle. Negative perceptions about the relationship also declined, making it all the more valuable to the individual. Both of these aspects were believed to encourage individuals to invest in their relationship with the help of relationship-promoting activities.

In another study published in 2017, researchers identified another factor linked to the quality of a relationship. Participants who were more satisfied were also more likely to disclose and be open about their fantasies with their partner.

"In my experience, partners who talk openly about their fantasies tend to have good communication, solid trust, and more excitement, which leads to great sex and nourishing relationships," said Kelly McDonnell-Arnold, a sexologist and relationship therapist. "This is the result of just the right combination of safety and risk."