Many writers consider their first draft to be their baby. It’s hard to let go of, and the idea of sharing it with others, opening the way to potential criticism, seems impossible.
Once your book has grown out of the first draft stage and entered the self-editing stage, there’s a little more distance between the two of you. The manuscript has matured a little, developed a few opinions…
The relationship between the two of you has changed from an imbalanced one of parent and child to one of close equals: best friends.
Best friends want to see each other grow and aren’t afraid to tell each other the truth in the process. However, they care about each other enough to be gentle about it.