One of the criticisms that I often see is that Henry is selling himself short by marrying Catherine, that he will eventually become bored with her because of the intellectual gap. I think Austen makes it quite clear that this is a compatible couple. Here are some thoughts from others as well as myself.
*“They share warm conversation, often comic exchanges, and an ability to express themselves with candor...” (Catherine Dominic) “There is a point to all this verbal skirmishing. Married life among the (relatively) leisured classes allowed much time together in an evening, and if conversation is difficult the couple is deprived of one of the chief pleasures of marriage.” (Gill and Gregory) We see this in the Bennet household.
*“Henry and Catherine have values in common. Like her he believes in family feeling and in the straightforward enjoyment of simple social pleasures.” (Milligan)
*“They represent a union of good nature and good sense. Catherine contributes a moral delicacy so free from self-conceit it hardly seems conscious of itself. Henry is a gentleman, in the best sense of the word, affable, completely in command and at ease, but with tender regard for the girl he loves.” (Milligan)
*They not only have a real affection for each other, but they like and enjoy each other’s company.
*Intellectually---In my opinion, the gap is not about who is more intelligent than the other, because I see Catherine as being intelligent but intellectually inexperienced which is where the gap comes in. Henry far outpaces Catherine in how much he already knows. Men have the advantage to begin with because in general, they receive superior educations by comparison. Second, Henry has about eight years of learning and experience over Catherine. And thirdly, Catherine has never been outside her country community nor has she read much beyond her fantasies giving her even further disadvantage. However, the events, her experiences and the people, good and bad, she has come in contact with, has opened her eyes to how knowledge is an important part of life. And, on meeting Henry and Eleanor, she has become like a sponge, eager at last to be a student of life. I like to think the time she and Henry had to wait for permission to marry, she has been busy soaking up a lot of good books. And Henry I’m sure will be more than willing and patient to continue to help her. Henry has such a head start in sheer volume of knowledge that Catherine will likely never catch up but as she is already a good conversationalist, they will do fine. As a clergyman and his wife over a parish, there will be much to do and discuss in this regard. They will read books together and discuss them and there will always be family and friends to provide many hours of talk as well...vacations and company... likely there will be children... I believe JA gives them a happily ever after! :)