Describe symbolism in A Handful of Dust by Evelyn Waugh

In Chapter Three, Brenda refers to her changing behavior and affair (Tony is still unaware), declaring it her new regime. Her habits; calling less, coming home less, and other behavior to slight Tony and their marriage remain, she decides, however, to dedicate an entire weekend to her husband, during which, she symbolically ends their marriage. He continues to be oblivious.