Could Susan's suicide have been avoided?

Lessing suggests Susan's suicide was difficult to avoid. 

One of the reasons why Lessing believes Susan's suicide could not have been avoided was because of her inability to recognize the limits of reason.  Susan is like her husband.  Both use “their intelligence to preserve what they had created from a painful and explosive world."  This dependence on reasonability is what prevents Susan from understanding the need for emotional connection in her life.  Her  “infallible sense for choosing...

Lessing suggests Susan's suicide was difficult to avoid. 

One of the reasons why Lessing believes Susan's suicide could not have been avoided was because of her inability to recognize the limits of reason.  Susan is like her husband.  Both use “their intelligence to preserve what they had created from a painful and explosive world."  This dependence on reasonability is what prevents Susan from understanding the need for emotional connection in her life.  Her  “infallible sense for choosing right” guides her actions.  Susan sees her life as one where mistakes need to be avoided.  She does not speak or interpret her life from an emotional frame of reference.  Rather she and her husband view emotions as "inner storms" and "quicksand."  This prevents her from articulating her needs, from speaking to her husband and to her loved ones in a way that provides her the help she needs.  It makes her to see her life as "a desert, and that nothing mattered.”

It is for this reason that Susan views her suicide as a reality in which it is “Nobody’s fault, nothing to be at fault, no one to blame.”  Susan is characterized as living a life that fails to acknowledge the limits of reason, and this is one way that Lessing presents Susan's suicide as unavoidable.