Mr. Bennet was very disappointed in his marriage - his beautiful, seemingly good-humoured bride became a tiresome wife lacking in good sense.

JA describes him finding pleasure in life through his reading and solitude in his library and delighting in silliness wherever he sees it - even in his wife and three younger daughters. JA implies, I think, that the alternative would have been for him to have taken a mistress. So he deserves some credit for not doing that.

I see him as withdrawing from harsh reality by refusing to take anything or anyone seriously.