I've given up the teaching job. It didn't take up all that much time, maybe 5 hours a week, but that cut my writing time from about 7 hours a week to about 2. Not good. Worse, I always had a corner of my mind on the look out for teaching ideas, instead of writing ideas. I wasn't getting any writing done at all.
Luckily my client had another, well-qualified teacher ready and able to take over, so I could get out of my mistake without damaging others or waiting months.