If you are a carer, you are entitled to a Carer's Assessment if you are living in the UK. Ring your local Adult Services and ask for this to be done. They will help you make decisions about the care you give, they will ensure you are receiving the right benefits and help with respite care to give you time for yourself.
I have been in your position with my mother and it is so wearing. She has just gone into a home and it is like a weight has lifted from my shoulders. Don't get me wrong, there is also a deep grief that I couldn't go on and every time I visit her I get flack which hurts but the day to day grind coupled with abuse has diminished enough for me to see light at the end of the tunnel.
At the end of the day, nobody has the right to demand you care for them. You can help them get care and offer ways forward to keep them safe but there is not an absolute right to expect that from anybody. Sometimes counselling can give you the tools to stand back but the one thing that you have to keep in your mind is that if they wear you down, you won't be any good to them anyway.
Maybe the first thing you should do is talk to Rape Crisis of how to get help to process your feelings. It is you absolute right to take time for that. Virtual hugs heading your way.