Which of these Roman rulers had an affair with Cleopatra?

Mark Antony was a relative and supporter of Julius Caesar and served as one of his generals during the conquest of Gaul and the Civil War. After Caesar's assassination in 44 BC, he joined forces with Marcus Aemilius Lepidus and Octavian forming a dictatorial triumvirate. A civil war between Antony and Octavian was averted by Antony marrying Octavian's sister. But despite this marriage, Antony carried on a love affair with Cleopatra, who bore him three children, further straining Antony's relations with Octavian. Eventually, the ongoing hostility erupted into civil war in 31 BC. When Antony was defeated by Octavian's forces, both Antony and Cleopatra fled to Egypt where they committed suicide.

Source: Wikipedia