You don't owe a detailed personal explanation. Your private business is just that. I would say something like, I will be closing my daycare as of x date. I appreciate the opportunity to provide an important service to your family. I cherish the relationships we have built and wish you all the best of luck in the future. I would also make sure everyone pays up front so you don't get stiffed! You don't have to go into the details. If they ask afterward just say I'm moving. Best wishes to you!
