How does the author guide our understanding of the ending in Woman's World by Graham Rawle?

Graham Rawle spends much of the book setting up a striking contrast between the "man's world" of public, practical reality and the "woman's world" of private, frivolous fantasy. While the reader can easily progress through the plot unsuspecting of the author's devious intentions, once the plot twist is revealed, one could decipher clues along the way.
Once it is revealed that Roy and Norma are two aspects of the same person—regardless of the explanation the author offers or does not offer—then the probability increases that one of them must go. Will Roy be able either to effect a full transformation into Norma, will he suffer a breakdown and seek therapy, or will he be unable to survive without her and end his life?
By conveying that an earlier Norma existed in Roy's life, killed by an automobile, Rawle sets up the new Norma's demise. Also, as the novel uses many of the conventions of older realist fiction, the errant woman must pay for her behavior. Norma resembles the fashion-obsessed Emma Bovary, who ended in suicide. In taking her life by moving vehicle, she also calls to mind Anna Karenina, who also led a double life that was exposed.