[link|http://www.amazon.com/Mating-Captivity-Reconciling-Erotic-Domestic/dp/0060753633/sr=8-5/qid=1163384999/ref=sr_1_5/104-2230991-9087157?ie=UTF8&s=books|Mating in Captivity].
It's mainly about the conflicts we have in our heads between the need for closeness and safety in a relationship with the desire for excitement and novelty to keep sex interesting. I can't say I agree with all of it, but it's a very interesting read.
Cheers,
Scott.