While I'm here, avoiding uni work...

Anyone had the memory of reading a book, and being absolutely positive there was a certain line in it, but when you go back and re-read, it's not there? I had this experience with Tehanu by Ursula K Le Guin. I was quite sure that there was this in there somewhere:

"After [x amount of time] she invited him into her bed. Three nights later, he found the courage to go."

Of course, it's not there. Is the line familiar to anyone? It's been driving me nuts!