I learned this from Steven Pressfield in his book, The War of Art. I've written about his book before. Such a powerful tool for those of us who are driven to create art but don't necessarily have the heart of a lion or the skin of a hippo.
I have known rejection. I felt it in my gut, and without saying the words, vowed to avoid that feeling again.
I have also come face to face with Resistance, even when I was experiencing "success." There is something about beauty and truth that Resistance can't tolerate.
Most recently, Resistance has gotten brazen. He shouts rather than whispers in my ear that what I'm creating is icky poo-poo. This makes going to critique group similar to standing in line to be flayed. Ouch!
I am me, the creator of stories. My stories are something I make, not me, not flesh and bone, certainly not my children. And my work always benefits from skilled eyes evaluating and guiding. This is why authors gush about the help they've had along the way in their acknowledgements.
We don't write in a vacuum, people.
Creating stories to send out into the world may be the most courageous thing we ever do, and we must do the telling with our whole hearts and souls.
Or who will care?
(I recommend Mr. Pressfield's book as a daily devotional for writers, especially if you need a swift kick in the pants now and again. The "chapters" are very short, sometimes not even a page long. BTW, I don't get a cut.)
How good are you at separating yourself from your work? Is critiquing something you welcome or something you dread? Is having someone point out a flaw in logic in your work a source of celebration or a crushing defeat? In what form does Resistance come to you?