"it can kill something inside you" is such a good way of putting it. Constant rejection can be incredibly demoralizing and demotivating: It makes you stop trying, because it seems nothing you do will make any difference.

Some writers do push through it (e.g., Cormac McCarthy), but others drown themselves in alcohol or other destructive habits. I'd love to see a good piece on how to deal with that in helpful ways. Thank you for giving me an idea (or maybe you could write it?).