I am going to sound judgemental, but really, is OP’s husband at the bottom of the pecking order in their family?
First the housework. OP says she does most of the chores (well that’s an improvement on some with husbands with dementia, life limiting illness or disability) - why not get a cleaner!
This boisterous dogs needs to be walked? Well the exercise is probably good for OP but if it is too much for her, there are dog walkers for perhaps a regular daily walk to give her some time to herself.
Finally - the daughter and grandchildren, OP doesn’t say how much time she spends and I’d be the last to discourage a couple of hours with the grandchildren - they probably make a change from her grumpy H.
Finally -H.
He is 80 - that’s not quite in his dotage, I count many 80 year olds among my friends, some in good health, most with joint replacements of one sort or another, some in better health than others - but none in their dotage.
These all sound like excuses - OP is clearly tired of having a H 17 years older than her - did she not see that coming?
It is hard to be locked into what sounds like a loveless relationship- or is it just inconvenient- but unless OP has a spare £4K or so available each month for a care home and indeed if her H likes the idea I think she may find it is not as easy as she seems to think.
Mattress causing back pain - or is it me getting old?? Advice please.