Anything "cathartic" is something you feel deep down, it's a gut response that has the power to make you extremely happy or dreadfully sad. Ask anyone who will answer truthfully, and they'll tell you that part of what made their first novel so hard was the feelings of protectiveness and insecurity that hit them like a sledgehammer. Nobody likes to think they are going to write a bad story, nor do they start out trying to fail. The images and ideas that fly around inside our minds do not always translate to a written page. The terrible truth is, if it's not on the page it didn't happen.
It sounds simple enough to say that book manuscripts are edited, re-rewrites can be a brutal process. It's a whole different thing to live through it, especially for the first time. Like it or not, that novel is a part of you. Might even be connected to something dark or ticklish you don't care to talk about. Even so, you're probably going to get up the nerve to ask somebody to tell you what they think about what you wrote. They'll read it and say...something. Editors read the whole thing and then say a lot. There are two things to remember about that feedback process:
Story is story, nuts-and-bolts details are something else. As you read this, somebody somewhere is writing a good story. While they write or type, they are not thinking about the many rules of gramma and what-not that are going to drive them insane later on. Spelling and punctuation are always going to make anyone's blood pressure go up. When any editor wants to pick a bone with you over the details of long/short sentences, they are in some small way doing this without your sense of style. What you see as too many short sentences can be that stylish part of you complaining about the lack of words that convey what you want a reader to see, think, or feel. That one single factor by itself should be enough for you take your own style more seriously. Don't just put words on the page because you know what they mean, choose them wisely pain a word picture that says what you feel.
There is no easy way to take the sting out of editing a first novel, it's always going to be hurtful. That's why so many writers read books about writing. That may sound counterintuitive, but it's not. Authors all over the world read things they would not write just to learn from them, to sharpen their own sense of style. That includes thick dry books written by editors about the subject of writing. We're all tempted to think we know everything there is to know about some subjects, even writing. When you realize that the art of storytelling is a life-long journey that prepares you to spin your yarn,
it becomes possible to take those punches. No matter how much they hurt.