I'm of mixed feelings about this. On the one hand, the fact that I have managed to reach so many words on a work of fiction is something of an achievement. I've never written anything this long before, and that makes this a more substantial work than anything else I've written.
But the fact that it's not done yet bothers me on a few levels. First of all, when I had originally plotted out this book, the plot structure I had planned for it felt like it would only require 100,000 words to tell the whole story. Clearly that's not the case. The initial setup (Part One) took about 45,000 words, and the development of the main part of the plot (Part Two) has taken 55,000 words already. It'll probably end up being 60,000 words. Now, this is not necessarily a bad thing, but it does mean that the book will take longer to write than I had originally anticipated. I'm rather eager to have the manuscript finished.
The second concern I have is the question of how much of what I'm writing is necessary to tell the story, and not just padding that makes the book feel long. Now, believe me when I say that while I've been writing the novel, every scene has felt necessary, and not like padding at all. Furthermore, I've got gnomi reading my new pages each day, and she tends to agree that what I've been writing is necessary to tell the story -- although she acknowledges that I may end up doing some cutting when I revise later on.
And the third question is marketability. My understanding is that publishers tend to prefer novels between 80,000 and 120,000 words. Given that Part Three has yet to be written, there is the distinct possibility that the book might break that 120,000-word mark. If so, it may end up being harder to sell.
But all these are just the thoughts that play out in the back of my mind, when I let myself go there. For right now, I'm just going to sit back and enjoy the feeling of having completed 100,000 words of the novel.