For a time, the protagonist lives with his former lover Gekrepten, and the protagonist's lover leaves him after the death of her son Rocamodour.  
One character in this work is an author gives the key to his apartment to another character and asks him to arrange his notebooks for publication as he recovers from being hit by a car, and another character is suggested to have gone to nurse one of the protagonist's former lovers with breast cancer, Pola.  For a time, the protagonist lives with his former lover Gekrepten, and the protagonist's lover leaves him after the death of her son Rocamodour.  The protagonist fears that his lover will have an affair with Osip Gregorovius, a fellow member of the Serpent Club.  Concluding with the protagonist perched on a windowsill, the protagonist of this work is cared for by Talita and Traveler, although he never finds his lost mistress La Maga.  FTP, name this novel about Horacio Oliveira which can be read beginning with Chapter 73, a work of Julio Cortazar.
One character in this work is an author gives the key to his apartment to another character and asks him to arrange his notebooks for publication as he recovers from being hit by a car, and another character is suggested to have gone to nurse one of the protagonist's former lovers with breast cancer, Pola.  
Hopscotch or Rayuela