Both Virgil's Aeneid and Lucan's Pharsalia depict conflict between men and women as well as conflict between men and men. In the Aeneid, the hero has to overcome his feelings for Dido in order to pursue his masculine imperial mission. He has the opportunity to abandon a destiny in which others will reap the benefit (since he will never even see the city of Rome, much less rule it) and live in luxury in a kingdom already conquered for him by a woman. Aeneas would not be a Roman hero if he did not escape from this conflict quickly and move on to the more serious, wholly masculine conflict with Turnus.
In Lucan's Pharsalia, Caesar has already won his conflict with Pompey when he comes close to being ensnared by Cleopatra. Unlike Dido, Cleopatra wants not to marry the Roman hero but to kill him. Although Lucan is dealing with real people who were alive fairly recently, Caesar's relationship with Cleopatra—and, for that matter, his conflict with Pompey—were sufficiently open to interpretation to allow him plenty of artistic license. It is the poet's choice to make Caesar an unlikeable character whose relations with Cleopatra do no credit to either party.
Caesar is not idealized as a model of masculine virtue in the way that Aeneas is. He is depicted as cruel and destructive, the practical victor in conflict, but not the moral one. While Aeneas's masculinity is associated with high-minded self-sacrifice, which means that he deserves to prevail, Caesar is a stereotype of masculine violence who simply destroys anyone weaker than he is. The closest analogy to his character in the Aeneid would be not Aeneas, or even Turnus, but Pyrrhus.