Hi @wightdancer I can see that you're received plenty of great answers from everyone here. Let me share my thoughts too... To answer your question, enough is when you feel enough is. It's truly sad to hear of how fast your wife is deteriorating. I've posted here in the past about a similar situation that I've been in with my grandmother. Her condition was getting increasingly worse - not at a very high rate. Taking care of her was beginning to take a toll on my family and I until we decided to hire a carer at home for her. We've hired this lady from Guardian carers and that has improved her life and subsequently ours. You say how you don't want to lose her to a care home. Have you considered having someone come in a few days a week or even to live in? It would be a person that she would get to know progressively and get used to having around. I think that this may be an option which could work.
Thank you andreasss86 your post helped me to decide to get a live-in carer; I am sure it is the right decision.