Walter's delusion

Franzen's Freedom's Walter is a case in point of how a story can be built around a character's delusions. Come to think of it, how else? We need delusions for any story to develop. Delusion one: that his wife could find complete contentment in him, which was forgiveable, under the circumstances. Second, much later, that his relationship with Lalitha was a sensible choice. 

The situation reminds me of Middlemarch. What would become of literature without these mismatches between kids and 50-year-old farts? And another question and an answer: What were Casaubon and Walter thinking? I know, we all know, what they were thinking.