I believe the most heartbreaking thing in the world to experience is verbal attack when it comes at a time we are trying to communicate with someone. This may be a somewhat culturally or environmentally induced state because not everyone communicates in this style. But I know few people who have not suffered this experience in some way. I myself grew up with passionate, emotional people who only knew, when they were feeling fearful or inadequate, to use words to attack and defend themselves or their position.
The times I have been faced with this I have tried to defend my heart by defending my position. I do not know if this was the most effective use of my voice but it was what I knew how to do. What I do know is that when it happens it hurts our hearts and, even as we defend, we retreat to a place that keeps us locked away from what is right in our world. It takes time to trust again; the relationship arena is changed when we are confronted in such a way.
I have learned by trial and error the wisest thing to do when this happens is to be the witness to what you know to be true. To listen to their pain without personalizing it, and simply retreat. Know, deep within your heart, that your response becomes the example through which change can be revealed, if not in the other person then certainly within yourself. You will be stronger for your quiet response and maybe, somewhere in the Universe, there is someone saying to you, "In you, I am well pleased." In knowing that to be true, there is peace to be found.