The theme that is raised in this novel that can be clearly related to the above quote is that of how Oscar is presented as a kind of anti-hero in this novel. He is perhaps one of the most unlikely heroes of love in the entire canon of literature: a nerd who is obsessed with fantasy games and science fiction who seems naturally to repel girls rather than attract them. Note how the above passage introduces Oscar:
Our hero was not one of those Dominican cats everybody’s always going on about--he wasn’t no home-run hitter or a fly bachatero, not a playboy with a million hots on his jock.
As a Dominican, the reader is going to have a series of expectations about Oscar, and Yunior in this passage is very clear to describe the ways in which Oscar does not meet such stereotypical expectations and does not match the norm of any normal hot-blooded Dominican male. And yet, although Oscar is shown to be so different, the novel at its conclusion shows that he in many ways is similar to Yunior. Both characters are looking for love, and although Yunior has many sexual partners, he is still unable to find love and keep it. Oscar, for all of his problems, at least manages to find love and savour it, albeit briefly. Therefore the theme that is introduced through the above passage is that of Oscar himself being an unlikely hero who deliberately defies the expectations of the reader.