It seems Mr Woodhouse didn't always lead such a secluded life.
In the, I can't say argument, more a gentle one-upmanship about the merits of their medical men, Mr Perry's and Mr Wingfield's opinions about the merits of sea bathing and sea air, Mr Woodhouse comes out with "Ah! my dear, but Perry had doubts about the sea doing her [Isabella's daughter Bella] any good; and as to myself, I have been long perfectly convinced, though perhaps I never told you before, [ I am sure he has!] the sea is rarely of use to any body. I AM SURE IT ALMOST KILLED ME ONCE"
So, in Mr Woodhouse's past life he ventured out of Highbury and visited the seaside.