What are the differences between the wives in Julius Caesar (Calpornia and Portia), and how do they interact with their husbands?
In order to understand these two women, we must look at how each of them is a product of their society.
Calpurnia is married to Caesar. Do these two people love each other? I would have to say yes. Caesar instructs Mark Anthony to be sure to touch Calpurnia as he runs the race. It was a celebration of fertility and it was believed that if a woman was touched by the winner, she would be able to conceive, something Calpurnia had not been able to do. That she is superstitious is a christian concept imposed upon a non christian society. Caesar himself consulted soothsayers and believed in omens. This was not unusual.
It would seem that both Brutus and Portia are younger. There is a strong feeling of passion with Portia. She loves her husband deeply and knows his moods well and can tell there is something bothering her husband. She feels the need to prove the extent of her love and, by extension trust, by giving herself a self inflicted wound on her thigh.
Perhaps the contrast is generational. The older love between Calpurnia and Caesar is more mature whereas Portia's love for her husband seems insecure. Perhaps with good reason since Brutus doe not confide in his wife. He would justify it by saying that he was protecting her but he still doesn't trust her enough to tell her.