How do you know she doesn't care? Is she posting in this thread and it is being missed? Or could it be that new1 is so hurt that no matter what she does/says he is looking only at his hurt and anger and discounting anything she does to show that she cares? Just because she cheated may not mean she doesn't care. As I stated before, we are hearing only ONE side of this.
I would agree as well that everyone has hidden fantasies... BUT that doesn't mean that some will ever share those fantasies with another human being. Some people never get comfortable and secure enough with themselves to share that part. No matter what the other partner does. Therefore some will never change, at least not on that subject, based on their up bringing, social conditioning, own insecurities, etc.