If I call him Sir, what should he call me?

Anonymous
Relationship wise nothing has been established between he and I. He said "But I am Sir right? and sir is always right." and I said yes and frequently address him as such. Sometimes he will call me sweetie or sweetheart. If i get a pet name though what should I expect to be called? If he asks me what he should call me what should I say?
If I call him Sir, what should he call me?
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