I'm borrowing from a blog (via Jaquandor's links) that cite some quotes from the Unbearable Lightness of Being that struck the blogger as life truths. One in particular had that affect on me:

Tomas came to this conclusion: Making love with a woman and sleeping with a woman are two separate passions, not merely different but opposite. Love does not make itself felt in the desire for copulation (a desire that extends to an infinite number of women) but in the desire for shared sleep (a desire limited to one woman).

Upon reading this, I felt the amazing desire to scream "DUH!!" For the vast majority of my sexual life, I have been able to separate the two emotions (or 'passions' as it were) very easily, but haven't quite seen it put to page so succinctly. Just based on that one I'll have to check the book out (although my judgement may have already been ruined by the movie).