It is behavior of a narcissist. These people often push a relationship too far as in showing up at your daughter and sending emails to other people. That is not normal. You should be relieved that you did not pursue this as these behaviors will get more irrational. The fact that she is an angry person and does not know the guidelines for a healthy relationship is also consistent. You should not be accused of being controlling to want a healthy relationship. This behavior is very erratic and is what a narcissist does. You are never going to have a calm healthy rational relationship with anyone that takes a breakup as she did. This is too over the top to be considered normal. They are about their needs and their wants. The relationship serves a superficial purpose and that is to make them happy. That is why her reaction to the breakup was irrational. Because your needs don't matter.
You may also want to look up a borderline personality disorder. This is the closest diagnosis to a narcissist as all their relationships are intense and erratic. They see you as a lover or a enemy but nothing in between. This is the type of behavior you are describing. It will be very enlightening.
Keep your distance and consider that this will never be a quiet and healthy relationship
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