But turning up the heat on those arousing imaginations could actually help strengthen your relationship.
In four different experiments, researchers analysed the effect that fantasising about one’s own partner had on the couple. In the first two studies, subjects fantasised either about their significant other or about someone else, before rating their desire to engage in sex and other nonsexual relationship-promoting activities with their partner. In the third and fourth study, romantic partners recorded their fantasies and relationship interactions each evening for a period of 21 and 42 days, providing daily reports on relationship perceptions.
The results, published in the journal Personality and Social Psychology Bulletin, concluded that fantasising about your own partner can increase desire, enhance the appeal of your partner and make you more likely to invest more time and energy in the relationship.
"Sexual desire is among the strongest forces in human nature, one that can induce ecstatic pleasure and a profound connection between partners," wrote the the study's lead author Gurit Birnbaum. "Even though fantasies are experienced in an imaginary world, they have their favourable grip on the real world."
"Dyadic fantasising may thus serve as a relationship-maintenance mechanism that helps partners sustain satisfying intimate relationships over the long run by boosting partner and relationship appeal and inhibiting engagement in relationship-damaging behaviours," he added.