Can you ever use the word former when it comes to a sub?

Diego leaned back against one of the steel girders on the dungeon floor of The Cage. He was helping another senior Dom, Master Gaige act as the Dom in Residence while the true Domme in Residence Mistress Thea recovered from her ordeal at the hands of the Reverend. Master Gaige asked for back up this evening, but Diego had no idea why. He had the whole dungeon floor eating out of the palm of his hand. His little sub Lilith watching her master attentively from the bar with several sub friends.