some insights on poet-playwright Frances Chesterton, wife of G. K. and niece of art historian Mary Margaret Heaton, and mentions the 2015 biography by Nancy Carpentier Brown, The Woman Who Was Chesterton. Brown blogs on Frances Chesterton here. Both writers paint a touching picture of a devoted couple. According to the 13 Dec. 1938 New York Times, G. K. regarded Frances as "in all ways a kindred spirit," and longtime G. K. friend E. C. Bentley (Trent's Last Case) called her G. K.'s "right-hand in all his dealings with the world" (qtd in Brown).
Of related interest: Frances Chesterton being mistaken for The Lodger author Marie Belloc Lowndes and her response: "I am quite willing to feel honored by [the] mistake, but they [Hilaire Belloc and Marie Belloc Lowndes] might feel aggrieved." Belloc (brother of Marie Belloc Lowndes) and G. K. Chesterton were close friends.