In the play Julius Caesar by William Shakespeare, what does Portia demand in the dialogue with Brutus in Act 2, Scene 1?

In Scene I of Act II, Portia knows Brutus is involved in
something big and believes he is hiding a secret from her.  She confronts Brutus and
asks him what has been troubling him.  Brutus dismisses Portia and says he just hasn't
been feeling well lately.  Portia knows that is not the truth and continues to prod him
deeper.  When he continues to deny her access to his thoughts, she accuses Brutus of
treating her more like a whore than a beloved and respected wife.  Their conversation is
then broken up by a knock on the door.  Brutus goes to the door, but assures Portia her
demand for confidence will be met and he will soon confide in her about everything that
is going on.