The day I saw Ian naked

In the story the Narrator of it is nameless but is described as either a male or female in the story. This person has a roommate by the name called Ian Bourn as he was relastate agent aka nude model. The person living with Ian Bourn sees him at a photo shoot because Ian told him or her to meet his there. When in the house, him or her start to realise something about the roommate, and that is the fact that he walks around the apartment that you two live in no clothes on, ass naked.

Who is the Narrator?