Moving to a Business address

My husband and I are starting the separation process. It will be hard for him to find a place to rent since we are very short on cash and credit scores are low. We have a small office that we rent. Can he move there and use that address to start the separation clock?

Sure. The separation period starts whenever you are living under different roofs; so long as he truly moves into the commercial space, with the intent to remain separated, your separation period will begin.