Like the Master and Margarita, both were married when they met, and they fell in love immediately. Shilovskaia was married to a well-placed lieutenant-general, and she met Bulgakov at Bolshoi Gnezdnikovsky pereulok, just off Tverskaya.
We learn Margarita's name only in Part II. Earlier the Master swears he will never reveal it.
Margarita also has a literary prototype in Gretchen (Margarethe) in Faust, and historical prototypes as well: In Chapter 22, Woland refers to a 16th century French Queen--Marguerite de Valois (1553-1615). Her marriage to Henri of Navarre, the future Henri IV, started the famous Saint-Bartholomew's Day massacre of Protestant Huguenots in Paris. Because she was childless, her marriage to the king of France was annulled. Marguerite de Navarre (1492-1549), another possible prototype who did have children, was the author of the Heptameron. Both historical Marguerites patronized writers. (Marguerite de Navarre was the sister of François I, grandfather of Marguerite de Valois. She was also herself the grandmother of Henry IV, whom the later Marguerite married. To add to the confusion, the University of Angers Library Site refers to Marguerite de Navarre as "Marguerite de Valois, reine de Navarre." No wonder Bulgakov conflated them!)