Parade's End, book 4: The Last Post
Ford Madox Ford1928

Christopher Tietjens, a brilliant, unconventional mathematician, is married to the dazzling yet unfaithful Sylvia when, during a turbulent weekend, he meets a young Suffragette by the name of Valentine Wannop. Christopher and Valentine are on the verge of becoming lovers until he must return to his World War I regiment. Ultimately, Christopher, shell-shocked and suffering from amnesia, is sent back to London. An unforgettable exploration of the tensions of a society confronting catastrophe, sexuality, power, madness, and violence, this narrative examines time and a critical moment in history.