It hurts

we grow, we make mistakes, we learn, we make more mistakes, it’s a continual process, don’t sweat it

with age come wisdom, and arthritis… and dementia, so you won’t even remember all the mistakes you made along the way, so don’t worry, you’ll figure things out eventually, at least enough to get by, and possibly even more than that

it is possible for people with PTSD to find treatment that has positive results, so again, don’t worry, and maybe try putting your focus where you can use it and benefit the most

and you never “have” to do something, life is full of choice and decision to opt out, things just present with consequences we have to decide if we can accept or not
so you could find ways if you desperately needed and wanted to, to “not see here on a daily basis”, even if not easy, it’s certainly not impossible, few things are.
And it’s sweet and noble you care for her so, but don’t forget to be selfish and care for yourself, then, perhaps, once you’ve made the effort with yourself, perhaps not only will you, and her, see yourself in a different light, but you’ll be able to care for her even more, and both benefit from it too this way around.

things never have to haunt you more than you let it and allow it yourself, even the worst of it, or if things don’t work/go as hoped despite efforts… in the end, everything in life is just “another lesson learned”, even if we repeat them several times or never quite manage to get it “right”.. doesn’t make it impossible or hopeless or that we are doomed forever… just challenging
all we can is try, and try to keep at it, until things get less difficult, even it not, or never, “easy”