Dear Felix
I have been thinking a great deal recently about balancing my career objectives with my family life, and after much deliberation, I have decided not to [TYPE OF WORK, ex. teach] for the year.
I have truly enjoyed my experience in teaching at the faculty, along with the friends I have made, and I would like to reapply for a position in the near future.
In the meantime, if you need a substitute teacher on short notice, please feel free to call me at any time.
You and the rest of the faculty have been very kind to me since I started teaching there and you helped make my experience there a positive one.
I hope to stay in touch with you.
Regards
Lydia