The word harlot has an interesting origin story dating from the time of the most important turning point in English history, the Norman conquest in 1066. When King Edward of England died in 1066, there were two claimants to the throne: his English brother-in-law, Harold, and a French nobleman, William of Normandy. William defeated Harold at the battle of Hastings, which resulted in a wholesale replacement of the English aristocracy by French noblemen. Although William is generally referred to as William the Conqueror, he’s also known as William the Bastard, because he was an illegitimate son of Robert, Duke of Normandy. Down through the centuries, European aristocracy and many historians have belittled William’s mother, Arlene, a pretty commoner who happened to catch the Duke’s eye. As a result, the English version of her name, harlot, came to refer to a prostitute or a promiscuous woman. Here, Portia is asking if her husband sees her as nothing more than a harlot. 

The sentence before this one makes a similar point. When Portia asks, “Dwell I but in the suburbs of your good pleasure?”, the word ‘suburb’ means the same as it would today: a neighborhood near, but not in, the city. But Shakespeare’s audience would know that conservative London officials considered the theater immoral and had banned the performance of plays in the city. So Shakespeare was forced to locate his theater outside the city limits, in the suburbs, where other banned businesses, such as houses of prostitution, were located. So when Portia asks if she only lives in the “suburbs” of Brutus’ pleasure, she’s asking if their relationship is nothing more than sex.