A string of infidelities occur in Charles’s story, representing the shallowness of modern values. Cara observes that the rift in the Marchmain marriage stems from Lord Marchmain’s childishness, implying that their marriage breaks apart because Lord Marchmain cannot take responsibility for the commitment he made. Rex Mottram never stops seeing Brenda Champion because he marries Julia mainly for social status, emphasizing that he doesn’t take their marriage seriously. In addition, Julia pursues marriage as if it’s a political alliance instead of a spiritual contract, highlighted by her willingness to marry Rex in a Protestant church when he can’t convert to Catholicism. Their marriage is expedient and is just as easily cast aside when the love between them becomes difficult to sustain. Charles also pursues marriage with Celia based on shallow values, hoping that her good connections will advance his career. Again, both parties cheat on each other. Celia encourages Charles to quickly forget her infidelity. However, when Charles pursues Julia, Celia acts extremely injured. The hypocrisy Charles and Celia treat each other’s infidelities with portrays modern marriage as valuing convenience and outward appearances over hard work and perseverance.
As an artist, Charles has a great appreciation for aesthetics, and he includes detailed descriptions of architecture and objets d’art throughout his story as emblematic of the values they represent. He describes how he first decorates his rooms at Oxford with trendy, modern pieces, immaturely surrounding himself with these items simply because they’re popular. After meeting Sebastian, he replaces these pieces, symbolizing his awakening to the beauty of traditional art. He goes into great detail describing the various rooms of Brideshead Castle, which all borrow from different architectural movements, symbolizing Brideshead’s ability to last through different centuries of fashion and taste and implying permanence. When Charles studies art in Paris, he mocks his fellow students who avoid the Louvre, which houses centuries of traditional art, in favor of pursuing modern trends. Here, he portrays young artists refusing to learn from the masters of the past as foolish and not destined for greatness.
War lurks in the background of much of the novel, a reminder that beautiful things must come to an end. Charles’s time in the army frames the novel, serving as a reminder throughout Charles’s happy time at Oxford that it cannot last. In Books 1 and 2, war mainly references World War I, in the form of Sebastian, Charles, and Mulcaster lamenting their inability to fight in it. Their longing for war represents a desire for a defining event, something that would cause them to defend their values; Mulcaster expresses this idea when he explains why he wants to stop the 1926 General Strike. Throughout Book 3, hints of the coming of World War II appear frequently in snippets of conversation, which Charles attempts to tune out in favor of spending time with Julia. His desire to isolate himself from the encroaching reality in his relationship with Julia is emblematic of its impermanence. As with all beautiful things, the relationship will come to an end.