I fantasise about my partner’s friends

When I have sex with my partner I frequently draw on fantasies to help me get turned on.

Often these involve me having sex with other men — including some of his friends. I don’t want actually to have sex with anyone else and the sex we have is always great, but still feel I am being unfaithful to him in some way. Or is this normal?

The psychiatrist and sex therapist Helen Singer Kaplan once wrote that “sex is composed of friction and fantasy”. The friction is self-explanatory, but the fantasy is still not terribly well understood. It’s strange when you consider that sexual fantasy is a virtually universal phenomenon. About 95% of men and women have sexual fantasies, primarily because there is a positive correlation between fantasy frequency, sexual function, and sexual satisfaction, particularly in women.