David falls in love with his boss's daughter, Dora Spenlow, at first sight. And, quite frankly, we're not quite sure why. David seems taken with Dora because she is lovely, paints flowers, and plays guitar. But she's not exactly a brain trust. Whenever David mentions things like housekeeping or accounting – things that a wife of her social station would have to know – Dora bursts into tears and accuses David of being a brute. Finally, David asks Dora's dear friend Miss Mills if he is being unreasonable to ask Dora to learn how to read a cookbook. And Miss Mills's response is not encouraging:
No. The suggestion is not appropriate to our Dora. Our dearest Dora is a favourite child of nature. She is a thing of light, and airiness, and joy. I am free to confess that if it could be done, it might be well, but — (37.37).
When Miss Mills says that Dora is a "thing of light and airiness, and joy," she means that Dora is not meant for anything serious. It might be a good thing – "it might be well" – if Dora were to concentrate on some serious thought about what she'll need to know for her future. But, Miss Mills decides, it just isn't going to happen. Dora is never going to be adult in her approach to things; she is always going to be a "favourite child" – note the child part – "of nature."
Indeed, Dora's whole character absolutely oozes childishness. She speaks plenty of baby talk, both to her annoying lapdog, Jip, and to David himself, whom she calls Doady. She throws tantrums at the drop of a hat, and has to be soothed out of them. Indeed, we think there's something significant to the timing of their engagement that underlines Dora's childlike nature.
Dora's father, Mr. Spenlow, is unaware of their courtship. David constructs these elaborate schemes with Dora's friend Miss Mills so that he can keep in touch with Dora. But Dora unfortunately has a resentful chaperone: Miss Murdstone (out of the blue!). Miss Murdstone discovers the letters David has sent Dora and brings them to Mr. Spenlow.
Mr. Spenlow is furious, and demands that David forgets the whole thing. But then, Mr. Spenlow suddenly dies, leaving Dora an orphan. And it's only a few chapters after this (after permission from Dora's aunts) that Dora marries David. So, while Mr. Spenlow is alive, David can't marry Dora. And once Mr. Spenlow dies, David immediately (and symbolically) takes Mr. Spenlow's place as Dora's caretaker. He spoils her and fusses over her as though her were her father as well her fiancé. And it's, well, a little weird.
Even Dora starts to realize that her relationship with David is perhaps not perfect. After meeting Agnes, Dora immediately grows to love her. She looks to Agnes to be a gentle, firm older sister. But looking at Agnes, Dora eventually asks David, "I wonder why you ever fell in love with me?" (42.56). David doesn't take Dora seriously here, but it's clear that everyone except David recognizes that Agnes is his perfect match.
Dora starts to wonder if she is clever enough for David, and if he needs a more equal partner in his marriage. He's such a young man himself that he's not ready to be married to such a dependent woman, in need of being spoiled and cared for all the time the way Dora does. Still, despite these concerns, Dora and David get married.
Miss Betsey comes to love her, calling her "Little Blossom." But like Miss Mills, she agrees that Dora is not cut out for anything serious in life. When David and Dora have their first big housekeeping fight, Miss Betsey warns David to love Dora for "the qualities she has" (44.63). In other words, David has to stop hoping that Dora will suddenly turn overnight into an efficient, well-ordered housekeeper. David takes Miss Betsey's words to heart and swears that he will stop trying to train Dora; it makes her unhappy and it makes him uncomfortable.
To help David grow more patient with her own imperfections, Dora actually goes so far as to encourage David to think of her as his "child-wife" (44.100). She means this name to remind David that adding up the household accounts makes her head ache and that trying to cook or manage the servants makes her cry. In other words, Dora may be David's wife, but she is also like a child. No matter how hard she tries, she cannot help being what she is. Very sweetly, she tries to assist David in his writing by sitting beside his desk and holding his pens for him. Even when Dora helps David, she does it in a pathetic manner.
Dora miscarries and slides into the long illness that will eventually kill her. On her deathbed, she secretly asks Agnes Wickfield to marry David for her. By inserting this detail about Dora's permission, Dickens may be trying to neutralize any negative judgments we might have of David for marrying Agnes after Dora's death. Even so, the whole Dora episode leaves a bit of a bad taste in our mouths: David's lack of respect for his first wife (even if he does love her) and his realization even while he is married that he should not be married to Dora seem a little ethically suspect.
At the same time, we have to admit that exposing these less-than-perfect emotions towards his wife make David seem more human and more honest to the reader. His confessions make the reader feel more sympathetic to his emotional pain in dealing with his "child-wife."