Start with the label, then move past it. “That is my wife,” “my boss,” or “a stranger” tells you the category. It does not tell you how this particular person affects you.
Ask: How do they make me feel? What do they do that creates that feeling? Which version of me appears around them? What can they give me or take away that nobody else can?
“She is my boss” is information. “She makes me feel like ten years of work could disappear with one sentence” creates an effect. Prepare that effect, then allow the actor in front of you to behave differently from what you imagined. Good relationship work makes you easier to affect. It should not lock the other person out of your preparation.
Read the relationship lesson