At Octavius’ home in Rome, Enobarbus and Agrippa are discussing Octavia, who is sad to leave Rome and her brother. They discuss Lepidus, and joke about whether he loves Antony or Octavius more. Octavius, Antony, Octavia, and Lepidus enter, and Octavius says how sad he is to see his sister leave him. He asks Antony to make sure this marriage brings them closer together, instead of pushing them further apart.
Octavia is passed from her brother to her new husband like a bargaining token. Antony and Octavius have arranged the marriage as a purely political stratagem, not as a romantic relationship.
Octavia cries at having to leave her brother. She whispers something in his ear, and Enobarbus and Agrippa debate whether Octavius will cry. Enobarbus opines that it would be bad for him to do so, since he is a man. But Agrippa says that Antony cried when he found Julius Caesar killed. Octavius bids farewell to his sister without crying, and Octavia and Antony leave.
Along the lines of stereotypical gender roles, it is appropriate for the female Octavia to cry, but Enobarbus thinks that Octavius crying would be shameful. Agrippa mentions Antony crying at Caesar's death, perhaps meaning to hint to Enobarbus that Antony is less masculine than Octavius.