Dear Mr. and Mrs. Durst,
In light of my current condition, I respectfully ask your leave for a brief time away from my responsibilities.
While my devotion to your dear children makes this decision difficult, I have taken it upon myself to find a solution that, I hope, will serve your household well. A good acquaintance of mine is experienced in the care of children, and I believe that she could assume my role during my temporary leave without difficulty.
I realize that my request is not without its complications. However, my years serving your family have shown me the depth of your understanding and compassion. I truly feel that I have become a part of this family, and I look forward to bringing another member of that family into this world.
Yours sincerely,
Klara