Dm cant entertain self

That last paragraph is more the slow gentle discussions over time to make her see and help you pull back, not part of the initial “can’t do for a good few days” plan.

Can you tell her in advance that you have a few hard days of work ahead and have plans of your own for the 2 days after that (boring things - dentist, dr, getting mending sorted, restock cupboards, and maybe a therapy appointment or Physio ) - you just need to catch up on all these, your life and house are suffering because you haven’t got to them recently, and they need to be done. DP is grumpy that things are sliding, and so are you getting depressed at the state of things. But on the 3rd day, you’ve arranged tickets for local plant fair/NT place she likes/visit to place she enjoys or lunch in a favorite restaurant...that you’ll be looking forward to catching up.

And while you are sorry you can’t see her for these few days longer than normal, it HAS to happen, but you are looking forward to hearing the news of her adventures in the meantime. Isn’t there an interesting WI talk or library event or (whatever local thing you think she’d be interested in) on X day that she would enjoy.

Would pre-planning, and having worked out how to say it in advance, be helpful? Just tos tart loosening the ties and making her aware that you also have things you must do? And slowly start to introduce the notion of things you WANT to do but can’t because of her - Bon Jovi concert, trip longer than she can manage or with too many steps, visit a place she has no interest in, play or film that she would hate...and that you are also entitled to enjoy your life.

I strongly second the suggestions for U3A. Lots of people who are on their own, looking to be involved in new activities and interests. Everyone is really friendly and there are so many different interest groups there are bound to be some that she will like whether it is theatre trips, local visits, arts and crafts, walking or even just meeting up somewhere.

Is there a university of third age (U3A) near you? They meet in our community centre where I live. They run different events for all different interests.

We also have a community transport bus which organises various trips every month.

Does she have any interests/hobbies? There are usually gardening/walking/photography clubs around. The WI?

WI, Trefoil or Townswomen's' Guild would all be good places to start.

Or my DM met loads of new friends via U3A when my DF died. U3A offers something for just about everything. It's a fantastic organisation.

Boundaries, boundaries. Decide what you want to do and stick to it.
She is young enough to make friends. FOG as others have said.

She's at a good age for making new friends - there are lots of people in their 60s and 70s looking for people to do activities with. No need to feel you're abandoning her to loneliness.

Nope! She is healthy and active and you have a job and work long shifts.
You need to set boundaries and not feel the 'FOG -Fear Obligation Guilt' that comes from some relationships.
It's difficult, the guilt can be overwhelming but you need to stand firm and break this cycle She will be annoyed, and may shout little at you, but, you have to hold firm.
I say all this from a similar situation.

Does she not have any friends or go to clubs etc? You need to be firm I'm afraid. Boundaries! Good luck !