She had to defend him in order to defend herself. That was why people were so prickly about their partners, even their ex-partners. To admit that Duncan wasn't up to much was to own up publicly to the terrible waste of time, and terrible lapses in judgment and taste. She had stuck up for Spandau Ballet in just the same way at school, even after she had stopped liking them.
In "Juliet, Naked" by Nick Hornby, the protagonist grapples with the complexities of defending her partner, Duncan, which serves as a reflection of her own self-image. The need to stand by him is rooted in a fear of confronting her own poor decisions and the time lost in their relationship. Acknowledging Duncan's shortcomings would mean admitting to a lack of judgment, something that weighs heavily on her conscience.
This inner struggle mirrors her past, when she defended the musical group Spandau Ballet despite her evolving tastes. Both situations highlight how people cling to their allegiances as a means of protecting their identity and choices, illustrating the deep connections between personal relationships and self-perception.