“Don’t feel guilty if you don’t know what you want to do with your life. The most interesting people I know didn’t know at 22 what they wanted to do with their lives. Some of the most interesting 40-year-olds I know still don’t.”
First, tell your wife exactly what you've written here. What you're about to do will scare the snot out of her if she doesn't understand your motivation.
The fact that you've posted something like this just about guarantees you've already decided to make a major course correction. Many people can work a lousy job they hate for 4 decades, get a gold watch at the end, and have as little to show for it at the end as you feel you have now. Looks like you're not one of them.
I wasn't one of them either. I told my wife almost exactly what you wrote up there. She asked me why it took so long, she'd know I was like that when she married me. We sold our house to be free of the mortgage, even though it was a bad time, moved into a rental and I've been working only on projects that interest me ever since. It was (is) scary. We've had to reduce our standard of living, but the days have turned from drudgery to adventure. Even if we end up living in a van down by the river, it will have been well worth it.
Only you can know whats best for you, but as someone who has walked this path, I encourage you to follow your heart. Poverty is uncomfortable, but regret is excruciating.
Edit: I'm serious about the tell your wife part. It instantly transforms her from hapless dependent (and one more worry on your mind) to co-conspirator and confidant. I just can't overstate what a difference this made for me.