Fun essay question! Well, let us consider the four main marriages of the novel when thinking about this: Mr. and Mrs. Collins, Mr. and Mrs. Darcy, Mr. and Mrs. Bingley and finally Mr. and Mrs. Wickham. If we consider each of these marriages in turn, we can see that on the whole, this statement is borne out.
The final chapter of the novel clearly indicates the way that Mr. and Mrs. Wickham are very well suited for each other in their moral character. Both are shown to remain just as they were and not to have learnt anything:
They were always moving from place to place in quest of a cheap situation, and always spending more than they ought. His affection for her soon sunk into indifference; hers lasted a little longer; and in spite of her youth and her manners, she retained all the claims to reputation which her marriage had given her.
Both are suited for each other in their general dissipation and idleness and inability to control their finances.
If we have a look at the Bingleys and the Darcys together, I think we can definitely say that both of these husbands get the wives they deserve. Note what Lizzie realises during the Lydia fiasco:
It was a union that must have been to the advantage of both--by her ease and liveliness, his mind might have been softened, his manners improved...
We can see that Lizzie's sense of humour and lively wit is exactly what Darcy needs to challenge his pride and serious demeanour. Bingley, too, finds his perfect match in Jane from her steadfast love, positive nature and kindness.
The only marriage that I think does not support this statement is that of Mr. Collins and Charlotte Lucas. Charlotte Lucas marries Mr. Collins after all for financial reasons and has no affection for her husband. When Lizzie visits her, it is clear that she has arranged things so as to spend as little with her husband as possible. Charlotte, in her common sense and goodness, clearly would lead us to conclude that she is not deserved by her husband. However, the rest of the marriages indicate that the statement is true for this novel, on the whole.