How does the relationship between Ben and Carla change after her arrival in Tripoli in the novel, A Map of Tripoli, 1967?

Upon her arrival in Tripoli, Carla notices that some of Ben's mannerisms have changed since she last saw him, including his style of speaking. He seems cold, ignores Carla, and voices that he dislikes what she wears. He may also be a bit of a philanderer, as, according to Mantini, Ben made advances toward his wife, Lucia, during a party, and showed a great deal of interest in her. He is pushy and extracts an invitation from Lucia to come to Villa Cappellini for horseback riding.