How does the story, M+M, explore the theme of imaginary worlds?

In the story, M+M, Martin spends much of his time in an imaginary world, responding to what he thinks Mariela would say to him, if they were still together. In his present moment, however, no one suspects that Martin is distracted because he is el comandante. Martin knows that everyone thinks “[he’s] the one who knows what he’s doing” (65). In this way, Pachico implies that one can appear to live in the 'real' world, when in fact, he / she spends most of their time in an imaginary world.