A recollection from Elsie Martinez, wife of Marty Martinez, an artist of the San Francisco (and Taos) group who knew Jack London, from Susan Goodman and Carl Dawson’s Mary Austin and the American West: 

[Lincoln Steffens had] asked [Mary Austin] to marry him. . . . He told us that he was certain Mary was cautious.  Mary would say, “I can’t see you until four o’clock this afternoon. My work’s going well.” Or, “I can see you at all until this evening because my work’s going very well.” 

Goodman and Dawson continue: 

So at Austin’s suggestion, they lived separately.  When she felt ready and decided to surprise him with an apartment that suited both, she found him there with another woman, his old sweetheart, Gussie.  That, according to Elsie, “finished up the romance with Mary.”