Portia is in total sympathy with her husband Brutus. Her only complaint is that he doesn't take her into his confidence. She is troubled by seeing all the furtive men visiting him at his home at all hours. She keeps insisting on knowing what is going on until he finally tells her, in Act II, Scene 1:
Hark, hark, one knocks. Portia, go in awhile,
And by and by thy bosom shall partake
The secrets of my heart.
All my engagements I will construe to thee,
All the charactery of my sad brows.
Leave me with haste.
We do not hear what Brutus tells her later on. Shakespeare evidently felt that would be redundant, since his audience would already knows it all. But in Act II, Scene 4, Portia knows everything about the conspiracy and has in effect become a co-conspirator. She is tormented because, as a woman, she is confined to her home and cannot go to see what is happening at the Capitol. But she is obviously hoping that her husband's plans will be successful. Towards the end of this scene she says to herself:
The heavens speed thee in thine enterprise!
Calpurnia, on the other hand, opposes her husband Caesar when he prepares to go to the Capitol where he expects to be crowned king. In Act II, Scene 2, she says:
What mean you, Caesar? Think you to go forth?
You shall not stir out of your house today.
Calpurnia feels sure that something dreadful will happen if her husband goes to the Senate House. She obviously senses intuitively that the men who have come to escort Caesar to the Capitol are not as well disposed towards him as they seem. Caesar should have listened to her, but he is driven by ambition and pride. He wants that crown. The wily Decius tells him:
...the Senate have concluded
To give this day a crown to mighty Caesar.
If you shall send them word you will not come,
Their minds may change. Besides, it were a mock
Apt to be rendered for someone to say
"Break up the Senate till another time,
When Caesar's wife shall meet with better dreams."
Calpurnia is overruled because she is a woman. Caesar cannot let it be known that he was staying at home because of a woman's dreams and a woman's fears. Caesar is a powerful man, but he is blinded by his ambition. After Decius finishes speaking, Caesar tells Calpurnia:
How foolish do your fears seem now, Calpurnia!
I am ashamed I did yield to them.
Bring me my robe, for I will go.
This is the end of the conflict between Calpurnia and Caesar, but Scene 2 does not end immediately. Shakespeare prolongs it with some incidental dialogue, but evidently the playwright's main purpose is to show a servant bringing Caesar his robe and helping him to put it on. That robe is of great importance in the play. In Act III, Scene 2, Mark Antony will be showing the mob what appears to be the same robe covered with bloodstains and shredded with what appear to be the sword and dagger strokes of the assassins. This duplicate robe will serve to represent Caesar's mutilated body, which is never shown to the mob but only described.