How to deliver bad news

Jack writes, “Two years ago I left a large utility corporation, where it seemed I’d never stand out, to accept a leadership role with my local parks & recreation department. Ever since my first day, I have been working non-stop, nights and weekends. The intensity of the job is tremendous. Things had fallen so far behind, and they expect me to do everything. My family is suffering, and now I’m considering an offer back at the utility company. My boss relies on me for everything, and I know he’ll take my leaving personally. How do I tell him, it’s not you it’s me?”