I'm the only earner (no DC).
At first DH was earning and I wasn't (studying).
Then we were roughly equal for about 8 years.
Then over about 4 years my career took off and his long term mental health issues came to a head and he took voluntary redundancy.
I assumed he'd heal and return to work. The first happened, the second didn't.
Now I work and he looks after the home. That's been our setup for the last decade and likely to be the same til I retire.
We found the situation is actually easier with one earner and one not earning than one high earner and one low earner. When we both worked but I had a more demanding job, he'd expect equal share of domestic work because on paper we both did the same hours, but he had a job that worked contracted hours only and was done when he walked out at 5, while I had a job that usually involved extra hours a few times a week and left me mentally drained at the end of the day.
Now we have clear responsibilities. I earn and work, he runs the house. He accepts that my job makes demands on my time, I accept that since he makes the home function his opinion about how we run our home has more weight than mine.