I was just having a last glance before going to watch TV and have something to eat. I try not to get too posty now, but to be fair I kinda get where you are coming from although this is not an answer to the original poster of the thread, though it may be of some help I guess.
I lived with my mum at home for about 4 years plus after my dad died and I did my best to keep her wish, I mean after all what could be better than remaining at home. But as time went by I was her sole carer and also worked 24/7. Dementia doesn't stop where we want it to (in hindsight) it keeps on getting worse. Some of us are very lucky to have a big supportive family, but some of us are left alone to deal with it in its entirety. I think if there is enough family and friends to help then yes keep on trying, but for sole carers we begin to run out of options, especially when we have siblings who won't help or pass before their time.
We blame ourselves for not coping, when the reality is quite different we were able to cope and do so admirably but what happens is that dementia begins to push that boundary. Its not that we are not coping, we just can't do any more than we can, the needs exceed what we can deliver as a human being with all of our emotions and issues to deal with as well as the person we love advancing with dementia. We do have to dig deep and ask ourselves how far can we go, but not only that we also have to ask when do we realise we can't do this role anymore that does any justice to the person with dementia. Caring is not just about doing or acting out the things expected of us, true caring is stating when we can't continue to do the best we can and having the grace to hand care over to someone else. It is painful and truly emotional path to take in all the hard decisions we have to make and it does stay with you always, BUT in time it gets better and we see things in a different way to where we were