Maybe she cares so much that it would hurt her to still have to see you and talk to you? and still see the pain and hurt in your eyes and voice each day.
I know its so hard to accept, but everything does happen for a reason. There is some wisdom in this otherwise it wouldn't have happened. We are only humans, that is why we don't understand. Maybe many years down the line you will look back on it and understand. This sounds like a fresh wound of the heart, dont worry, time heals all, even when you dont want to be healed.