Old Mike, of course it's possible without a supporting spouse. If you've accumalated enough savings, which can be topped up with part time work, then full time study is feasible.
I quit my (well-paid) job to retrain a decade ago. It was a tough decision, but in the end I wanted to try something new that I had a passion for.
Never looked back, even though the year of full time training was a financial drain and I was starting at the bottom of the ladder when I finished studying.