Like a Million Tiny Knives
That's exactly how it is for an author to be edited. Your book--your baby--is submitted to someone whose job it is to point out what's wrong with it. That line you thought was cute? The editor suggests you take it out. The punctuation you struggled to get right? She doesn't agree. And the plot: "What about this? Why doesn't she do that? How could he have missed the clue here?"
The first thing a writer (and maybe the parent of a special child too) has to do is give all that advice some distance. Experienced writers suggest skimming your editor's corrections and suggestions once as soon as you get them, then walking away for a few days. Your first reaction tends to be, "How can she/he be so DUMB?" or "Why doesn't he/she get how great this story is?"
Later, when you've talked to yourself a little, you can come back to the edits and see them more objectively. First, you asked for this criticism. You submitted the book to someone you trust because you know your selfish author's eye isn't going to see its faults.
Second, the editor isn't trying to hurt you, at least not if he/she was well-chosen. Editors are supposed to be honest, and they look at your work as a reader will, without your built-in understanding of what you meant to say and why you chose to tell the story a certain way.
Third, you don't always have to take the editor's advice. While it might be more difficult in traditional publishing, the author has the right to say, "This is why I think my way is effective. A good editor will listen and perhaps discuss, looking for a way to strengthen and tighten the work without taking away from what the author sees as her style." Of course that doesn't work with spelling, punctuation, and such, but those are less important to the overall story anyhow.
It's frustrating to be told your "baby" isn't perfect. It's hard sometimes to accept what the experts say. Still, I find that editors make me rethink my work and look at it from a new vantage point. Even when I don't wholeheartedly agree with them, I accept the possibility that I wasn't as clear as I could have been and might need to rework a sentence or a passage.
It's difficult when someone makes you see your child with new eyes. Despite their comments, you won't love your child less, but you might see ways to make him fit better into the world outside.