The XX Factor

New Desire Lab Question: Lust in Long-Term Relationships

At the risk of too much repetition, I want to thank you all again. So little is known about the importance and content of fantasies in women’s sexual lives-it’s almost stunning how little this subject has been studied in any formal way-and so many of you wrote in with candor and eloquence. It’s a subject we’ll return to.

But for now, let’s switch to another mostly unstudied topic-desire over the course of long-term relationships. For the purposes of this discussion, let’s define long-term as a year or more.

There’s a theory that has some currency among sex researchers and therapists: that over time in monogamous relationships, women lose desire more than men do. Not much data exists; I’m aware of only one large study on this subject. But the thought is that women’s libidos need more spark in order to ignite, and so women are particularly susceptible to losing desire as they remain with the same partner. It’s an idea that runs somewhat counter to the assumption that female desire tends to depend a great deal on the depth of relationships, on intimacy.

Again, though, we’re talking about an unproven theory. And the hope is that the Desire Lab is a chance to examine the truth of such thinking. How has desire changed for you-or has it changed at all-as long-term relationships have unfolded? How have the changes felt? And how do you explain them? Please send your responses to desirelab@slate.com . As always, your identity will remain confidential.

I’ll start posting your replies as they come in, and in the meantime, much of your thinking on fantasy is collected here .