First, co-morbid means diagnoses occurring at the same time. So for you PTSD and bipolar II are comorbid.

That sounds a little like exposure therapy but exposure therapy is focused on the things that cause PTSD reactions. When I did it I wrote out a bunch of really bad scenarios from my past that still bothered me. I had to pick the one that bothered me most (which was actually the one I could handle coping with then) and I recorded myself reading that story and then every day did different techniques while listening to the story several times. Then in therapy we talked about the memory and my reactions until it no longer was so disturbing and then we went to another story. The kind I did is supposed to be one session weekly for 12 weeks; it took me 2 sessions weekly for 4 months but the BP and anxiety and OCD I already have made it harder and I needed times that we backed off or times we stayed on something longer than would be typical. I won't lie, it is incredibly hard work but it was worth it in the long run.

There are other PTSD treatments that I don't think are as aggressive; EMDR is one that I know very little about but someone on here will. I briefly discussed it with my therapist but it would have meant seeing a 2nd therapist for that technique because mine isn't trained and that didn't seem like a good idea.

If this is all new to you you may need to ease into it before tackling huge issues but I'm not a therapist so I really don't know how that works.