Op this needs to be reframed, as you have said you don’t want to end your marriage, so I assume you have considered this option in detail and really it’s in your best interests to stay.
You can’t stay as you are though, so unhappy and miserable, it’s time to really start taking charge.
Book a decorator for the rooms impacting you the most.
Start holidaying with family and friends and dh.
Appreciate the extreme exhaustion your dh is experiencing day in and day out, as he continues to work to support you, can you see that if you were doing 60 hour weeks you might feel the same or worse? Can you start taking care of him instead? Run him a bath, show some empathy? I’m sure he doesn’t want to work so hard, but has no choice.
Look at old photographs and videos of your younger selves, celebrate how far you have come.
Mske friends, join clubs, launch a little working from home business, study something new. Lose weight, tone up. Do something completely out of the ordinary.
You are in a static, comfortable cocoon, but it’s draining the life energy out of you. Take back your life. Throw a party. Make this last chapter count.