Studies of self-expansion — broadening your experience through novel and growth-oriented activities — suggest that when long-term couples do something new and engaging together, this is associated with greater sexual desire and satisfaction. Researchers have found this using different approaches, including daily diaries, longitudinal data and experiments.
But having a rich separate life is not an automatic aphrodisiac either. Another series of studies found a more complicated pattern: personal growth and novel experiences could coincide with greater passion on particular days, while chronic expansion outside the relationship and without the partner was under some conditions associated with less intimacy and passion.
So “the more distance, the more desire” does not survive scrutiny very well.
Another relevant concept is partner responsiveness — the feeling that your partner understands you, accepts you and cares about your needs. Research has associated this perception with greater desire for a partner, although the strength of that effect varies with context and participants.
The picture that emerges is rather appealing: long-term desire may be supported not by artificial unavailability, but by being able to experience closeness and curiosity at the same time.
The person beside us may be deeply familiar. The relationship still does not have to be a finished book that we read years ago and put back on the shelf.