If it makes you both happy, then it's no-one else's business.
But I think the general doom and gloom about 'domestic drudgery' and how unhappy people are living together is a bit off. You can't look at forums like this and decide it's the normal state to be having problems; it's a self-selecting sample. Of course you hear about the unhappy things and don't get so many posts about the good stuff, people usually post when they need help and advice. You don't need help and advice when things are good.
I had a couple of unhappy relationships and swore I would never do that again. I even thought much the same as you, the ideal would be a relationship but living separately.
then I found the right DP at last. I look at him every day and think how much happiness he brings to the little everyday stuff of a shared life.
And I really don't get the domestic drudgery angle. If there's 2 of you living in one home, then you only have to do half the domestic chores and stuff you would have to do if you lived there alone? There's not more work because there's 2 of you, the house is the same size, there's one bed to change, there's one bathroom to clean, there's one dinner to cook, 1 living room carpet to hoover, and 2 of you to do it.
"To watch someone you loved and respected degenerate into a breathing sack who shits him/herself and can't remember what day of the week it is?"
I find this really offensive and nasty. This is my Dad, according to that poster. To us, he's still a human being who is much loved and who loves us, who deserves his dignity and some care for all the things he has done for us for over a lifetime, and we treasure the remaining time we have with him. He is not just a 'breathing sack', thank you very much. We still love and respect him.