I am in a very similar situation. This is how I manage things….
first of all, you need to accept the situation, choose your battles, and make a different life for youself. Join a new group/ get a new hobby/ interest.
So for me, I got myself a bike, and I just go off on a wee bike run, fresh air and exercise thrown in and I also got myself a second hand camera, go to the local park and check out the birds and flowers, again fresh air and exercise. Concentrate on your own mental health and well being.
I totally get needing to have your own space and me time….
We are now in seperate bedrooms so I am lucky enough that I do have my own space. I have decorated it to suit my taste, it’s my wee sanctuary. I have a tv so can watch programmes that interest me in the evenings.
I also escape to the bath just to get away from him!
My working pattern is similar to yours, 3 days in office, 1 day working from home. 3 days off, on one of those days off I escape, go someplace wether it visiting my parents, go out walking, meet a chum for lunch.
You mention you have a garden, if he has savings, could you persuade him to get a shed with windows / garden room / summer house , where you could create another space.
“can't see a future for us because I hold such anger and resentment now, and everything. about him has become so difficult for me I can't see a happy relationship for us going forwards”
I, on occasion, still get angry and feel resentment . It’s so fecking hard.
I have lost my partner, my best friend, my soul mate, financial security, friends . However, I have accepted that this is it, I choose my battles, and have created a different life for myself in order for it to work. It’s very easy for others to say to leave him, but that’s not always possible.
Sending you a virtual hug 🤗