Mary Lyulph Stanley, née Lowthian Bell, was married in 1873.
She may have known JW in the mid-seventies, when her name appears in an address book (#12714).
Who Was Who: A Companion to Who's Who, London, 1920 et seq.; Macleod, Dianne Sachko, Art and the Victorian Middle class. Money and the making of cultural identity, Cambridge, 1996.