Mark Antony had just accepted Octivia to share power with as partner in crime, when the Senate tried to regain control over Rome. Antony and Octivia didn't like the idea of the Senate having control anymore, so they sentenced all 130 members to death.
We have to end this and them!
It must be done!
Mark Antony was so determined to show his dedication to his partner, that he divorced his then wife and marry Octavian's sister Octavia. After this the Empire was split between them (Octavian on West and Antony on East).
In Egypt Mark Antony met Cleopatra and fell in love with her. Soon after he divorced Octavia and remarried to Cleopatra. Octavian (being the good brother he was) was mad that his sister was being treated this way. He didn't need to convince the people of Rome of his badness as they were mad he married a foreigner.
Next In 40 B.C the Parthians invaded Roman territory, taking Syria, Asia Minor and placing Antigonous as acting King in Judaea. Mark Antony then decided to oppose the invasion and sent his general Publius Ventidius. Immediatley following this he wanted to retaliate their invasion by invading Parthia but he needed Mark Anotony's army. The command given to mark would not be followed as his army was busy in Sicily where a rebellion of Sextus Pompeius was occurring.
We can't up and leave to Syria!!!
This disregard of a command created a dispute with Octavian but a treaty was signed in 38 B.C, Tarentum. Soon after Mark Antony returned to Egypt to and made Cleopatra lend him money he needed to form an allliance with Herod the great. So in 37 B.C Herod and the Roman Army took back Judaea.