Im a male in 40's; long term girlfriend in 30's

During after being lovers for six month, she found out she had HIV. I loved her and wanted to stay with her no matter what. So I did. she battled her way through chemotherapy for AIDS bone cancer. During that time we still had a great sex life and were very close, even though she was so ill and as bald as a billiard ball. I moved in with her.
We then seemed to bicker a lot about small things, but after we found a way through - say about having a room we both liked - then we would be happy with the result.
Then even though I was earning a pile of money as a freelance consultant, she started getting very stressed. She was used to never having to find work (she was a nurse) This led to loads of arguements about money. To please her, I went for a permanent position, the dot com crash happened and I had to go back to freelancing.
She filled her time with studies

Then out of the blue about 3 years ago she started getting neurological symptoms, having previously been pretty fit and healthy. Within a few months it turned out she had a HIV related brain illness and within another couple of months was brain damaged with loss of vision (hemiopnia) and left sided hemipareisis, so she now needs 24 hour care. She is mobile under total supervision around the house.
We have a carer during the day, I care during the nights and on Sunday
She is extremely vulnerable - if there was a fire she would be unaided to escape unaided.

Like many people with her stroke-like symptoms, she has violent mood swings. I can leave the room and come back to a different person. I find this very draining
We used to have a very chilled out, relaxed relationship. She was a very gentle peaceful person. The person I am with now is always ready to turn wine into vinegar. She hates needing me to do things for her. She sees me as now a negative, critical parent. I hear myself and sometimes I am...

We have almost no social life. If we go out, she is silent during the meal as attempting to talk can trigger a coughing fit that can lead to her throwing up. This happened at our last meal with friends at home. Rather than dealing with it, she tries to pretend nothing happened, then goes into self-hate later. When we go to the cinema, she looks at her watch
all the time and ignores me.

I have seen what happens when she is not taken care of... eg public hospitals are -very- hemipareisis unfriendly; nursing staff are not trained and lose pateince - she then tries to go to the loo by herself and falls badly; she demands to self-medicate and then forgets.

I have been the primary carer for the last three years - I have been able to work only part-time with an employer who is very understanding and extremely flexible eg if her carer doesnt show up, I cant go to work. My credit rating has plummted because of this. Her state benefits are much higher than what I earn.

I have not had a holiday in five years. I havent had sex in three years.
We bring out the worst in each other. She is sometimes like a lamb, mostly like a wolverine.

If I left and anything happened to her, I couldnt live with myself. The odds are, based on previous experience, that she would be at physical risk.

I have been in counselling (my situation made the -counsellor- cry) and therapy for some time. I feel they have kept me sane.

The truth is, I dont know what to do. Sometimes the only way I get through the day is think of e.g. the endurance of villagers in Afghanistan, who have had to cope with earthquakes, famines and constant wars, but still go on.

Thank you for taking the time to read my ramblings; I would be very grateful for any insights as I feel very very stuck.

xx