Numbed, asking someone to help with your healing is a lot to ask when they are not really qualified to do so, or can really understand the needs of someone who struggles with PTSD.

Your GF can learn how to be supportive and allow you to talk things out, but it's really hard for someone to give the right advice that will be more helpful/healing. I have a really hard time with my husband, I reach out to him for support and he tends to say the wrong things back that end up triggering me. I want my H to stay calm and just let me vent when I need to instead of him interrupting me and challenging me at times.

You can "try" it a little, but make sure you realize that your GF is going to fail to respond sometimes the way you need it.

OE