"I identified more with Julien Sorel's relationship with Mme de Renal than his one with Mathilde de la Mole."

This refers to the novel The Red and the Black by Stendhal (the pen name of Marie-Henri Beyle), a French novelist (1783-1842).  Despite living during the Romantic period, he was one of the earliest and most important practitioners of Realism.  He is particularly admired for the psychological awareness of the characters he created.  The Red and The Black (1830) is a two volume novel depicting the attempts of a provincial man, Julien Sorel, to rise above his simple upbringing and achieve a higher social standing.  He is held back by his naïveté and idealistic fantasies, which in turn allows Stendhal to depict 19th Century French society in a satirical and critical light.

The novel can be read online here.