She married Rt. Hon. Hugh Oakely Arnold-Forster, son of William Delafield Arnold, in 1885 at Highworth, Wiltshire, England. They had four sons. They were :
William Edward Arnold-Forster (8 May 1886 –1951) artist, author and Labour politician, married Katherine "Ka" Laird Cox in 1918. She was the former lover of Rupert Brooke. Their son was Mark Arnold-Forster. After Cox's death, he married Ruth Mallory, widow of George Mallory the mountaineer.
Mervyn Nevill Arnold-Forster (21 March 1888 –6 May 1927)
John Anthony Arnold-Forster (20 September 1889 –1958), married Daphne Mansel-Pleydell in 1919. Vanda Morton, biographer of Nevil Story Maskelyne, is their daughter.
Hugh Christopher Arnold-Forster (9 December 1890 –21 July 1965), who rose to become a Commander in the Royal Navy and served as Deputy Director of Naval Intelligence during the Second World War; married Marcia Buddicom in 1922 and Frances Brown in 1948.