Hi, I am a new member as well, my husband and I have been living with his PTSD for 8 years now. The other ladies have given some great advice already that I would like to reiterate: do not be economically dependent on someone with PTSD if at all possible, especially if he and his therapist have not been able to formulate good plans for your husband's emotional storms (which of course include the extreme numbness he is feeling right now). If you have a decent job, then there must be a way to find your own place to live. Involving financial reasons for you and your DH to stay together will involve guilt and co-dependency, which completely takes away from the point of staying together through commitment and love.
From my own experience, reasoning with someone in the midst of an emotional breakdown is useless. My DH, too, wanted to move out and leave at times, even after we had children together. Asking your DH to abstain from life-altering decisions right now is the best argument: maybe he would be open to a compromise by having one of you move out for a while to a motel or a week-by-week (or even month-by-month) rental unit. They are usally pretty affordable and you two would still be in the same area while giving your DH some distance. It will also help you to distance yourself from him, too; it is very, very hard to live with a spouse with PTSD and having your own routine, finances, and sense of independence will go a long ways to shielding yourself from the fall-out of your DH's emotions. It is also quite possible that he may in some way be trying to protect you from depending on him, by acting so unpredictable; he may be scared or resentful of people depending on him, so your DH may need to see that you can stand on your two feet.

I hope and will pray that you and your DH can work through this. It is incredibly difficult and often I am amazed that my DH and I are still together. But we are, and so are many others here. It is possible. We will be thinking of you and please keep us updated.