Who is Dottor Alessandro Postiglione from The Sixteen Pleasures and what is their importance?

Dottor Alessandro Postiglione is an art restorer who meets Margot the day she arrives in Italy. He offers her a place to stay but she refuses. The two meet again at a later date and have coffee together. He than arranges for her to stay in the convent where his cousin lives. Postiglione assists Margot with the restoration process, during which time the two develop a friendship and later become lovers. The couple never marries.