PTSD & emotional defence mechanisms ...
You could get any number of different responses but in my case it tends to lead to me shutting down emotionally until I can process what has happened.
I was recently involved with someone who thought that I was purposely closing her out and perhaps trying to punish her by withdrawing my warmth...but it wasn't so. I tend to be more vulnerable than the average human being in society because of my particular experiences through life. When subjected to pain, who wouldn't withdraw themselves. If your hand gets too close to the fire and starts to burn, do you not pull it away?
One of the realities of living with PTSD is that I have a defense mechanism that closes down all my emotions - it's a bit like being surrounded by thick, metal doors. Nothing gets in or out until I've managed to sort out whatever's just happened.
If you're in a relationship with a vulnerable person, take care and communicate openly and effectively in a sensetive manner. It doesn't mean that we've stopped caring for the person that we've had the upset with ... just that we need time to deal with what has happened.