Welcome here to the Forum, I'm glad you have been reading in this place over time, it may make it easier now you have spoken out.
I have been a male sufferer from PTSD, depression bouts and constant anxiety, which came in waves not necessarily regularly. I wanted to withdraw, had no mental capacity left to interact even with those I loved, and was not sure about anything, myself induced.
Even so the worry I was driving everyone away by my behavior as well as hurting them was very real and constant.
Eventually I had the correct medical help and things improved out of sight. I lead a pretty good life nowadays.
The two things that stand out from your post are firstly that you partner is not being treated for some major problems, and if these are not taken into account will probably hamper the good that is being done by her existing medical support. Until I was completely frank and disclosed all my problems treatment only marginally helped.
Can you persuade your partner to tell her psych her full history? It may be the most productive thing you can do for her.
I can't speak about separation, I just wanted a quiet room. I'd imagine it might make her worry more about driving you away, but that is just a guess.
Now secondly you mentioned you have anxiety and depression. May I ask what support is there for you? After all you are undergoing a long term high stress and worry situation.
I wonder if you are under medical care yourself, you would not want you conditions to worsen due to the strain you are under. Also is there anyone, family or friend, to give you personal support, listen, offer perspective, and maybe even practical help?
This makes a huge difference if there is such a person.
I hope to hear from you again