A friend and I had a short discussion about writing versus editing. Briefly put, the initial act of creation often seems joyful in contrast to the plodding, methodical effort needed for pruning extra words and revising paragraphs. There is no better feeling than uncorking the bottle of creativity and allow the words to flow.
As my mother would say, sooner or later it's time to do the dishes. My current WIP stalled a bit after I had written the final sentence. In my defense, winter was over and I have other hobbies besides writing, particularly in spring and summer. Excuses aside, I have to admit that no agent or publisher wants to read anybody's first draft. A lot of authors don't enjoy reading thier own first draft. The word repetition, overwritten sentences and plot inconsistencies grate like fingernails on the blackboard.
The first thing is to take time away from the book before begin the edit. It will seem less like your own work to read and the job of editing will seem less like auto-amputation. Second, if you haven't done so, join a critique group. Not so much to have others provide feedback, although that is helpful, but to get in the habit of looking at a manuscript as an editor would. I learned that after I read exerpts written by others in the group I was better able to recognize problems in my own writing and to take pride in fixing them.
Remember in elementary school how much you hated seeing those red lines underneath your writing and the comments in the margins? No? You're luckier than me. Even in college I had an aversion to criticism, no matter how benign. I'm finally adult enough to realize criticism makes me a better writer. Putting my work under the microscope is a job that takes more time than creating prose in the first place, but the result can be a beautiful thing.