Umm, yes it is debilitating. Your wife is severely restricted from participating in normal everyday activities -- LIKE GOING HOME!
Quote: Make no mistake about it OT, THIS is the major source of my W's problems.
Clearly. But, it is also a major source of YOUR problems (you probably worked nights so much simply to have an excuse to get a much needed break). And an incredibly damaging factor to your R. It isn't just slowing things down, it is causing great harm.
Look. This might help you a bit. Think about your W with some compassion. All that "free" time you think she has is not at all free for her. She is not able to simply go home and relax. While it feels to you like she has oodles of free time, it doesn't FEEL free to her. In order for her to get "down time" at home, you have to be there taking care of things. But this is incredibly nonfunctional and destructive in so many ways. Neither of you has enough down time because she is unable to get any during that 7 hours each day. Then, you turn into a caretaker/martyr at night. Not good.
You are enabling her to continue this lifestyle by making sure to accomodate her craziness. This really needs to stop. She needs to get help. You can't force her to. But, you can insist on a more balanced R in which the household responsibilities are more reasonably shared. And yes, this means she needs to be more since you work full time and she does not.
One idea, and this is not sarcastic... Maybe she could get a part time job to pay for a companion so that she can be at home during the week. (That this is possibly a reasonable interim solution shows that her panic disorder really is debilitating... She cannot function as an independent adult.)