Antony, Octavia, and Caesar are back at Caesar’s palace in Rome.
Antony promises Octavia that though his work will take him away from her often, he won’t indulge in any monkey business, no matter how naughty he’s been in the past.
Caesar leads his sister away, and Antony meets with a soothsayer who tells him he should have never left Egypt, and should get back there ASAP.
Antony asks whether he or Caesar will have better fortune, and the man replies that Caesar will.
Further, Antony should stay as far away from Caesar as possible, as Antony’s fortune is muted, and his greatness lessened, whenever Caesar is around. Antony agrees, and announces that though he married Octavia to make peace, he needs to return to his girl in Egypt as "I’ th’ East my pleasure lies."
In a totally unrelated side note, he sends his soldier Ventidius to Parthia (modern-day Iraq) to fight on his behalf. (Parthia was one of Rome’s last surviving major enemies in the East.)