Although James Gunn posited that reading was like sex, I've formulated another theory: writing a novel is nothing like sex.
I've just finished the first draft of my second novel, and perhaps I might have a different perspective when I've finished my tenth. Also, publishing the novel may put a different sheen on the whole thing--I'll let you know when and if the time comes. In the meantime, here's the support for my theory:
1) After the "first time," I wasn't completely sure I wanted to do it again. After all, it was a lot of work, and when I was finished, no one but me seemed particularly excited about the whole thing.
2) When I went back to work on it some more, I found that it got better with the assistance of a whole group of people, rather than the close attention of a single partner.
3) Although I learned a lot from my first attempt, I wasn't completely confident that my second attempt would be that much better than my first. (OK--maybe this one isn't a complete dissimilarity).
4) When I finished the first draft my second attempt, I knew I had a whole lot of work ahead of me before I got it to the point I'd be completely satisfied.
And here's some tips for those just getting started: do a little every night, don't get discouraged if you lose your drive--it will come back if you just give it a chance, and, above all, remember not to get too hung up on an extended metaphor--it can get old fast!