I have had a somewhat similar experience with PTSD symptoms and emotional stability-- although for me my biggest issue was not so much affective but just reactive to people and things in my environment. In the past year I have also dug into the trauma issues very deeply and my symptoms (mostly dissociative) have almost entirely gone away. I just had this instinct that I needed to talk about really tough details and how remnants of these experiences were still floating around my daily life, and to disclose a trauma I've never talked about before to previous T's.

For me mindfulness is not so much about exercises but noticing when I am fully present (and usually fully enjoying) what is going on in my life at the moment. I "practice" mindfulness in my daily life, I am not so into the official exercises. I guess I "see" you through your posts as a mindful person, and what I mean by that is that you seem pretty grounded and self aware about what is going on with you. You know the things that get you into trouble, you work hard on them. You seem like you are very present in your life (I think you said, either here or somewhere else, that your dissociation is much less than it used to be). Maybe you don't like reading about mindfulness per se, and might enjoy something that is more theoretical and not let's do this mindfulness exercise.

Has your T recommended any Pema Chodron books to you? For some reason I think that these might be a good vehicle for you.