Secrecy
From unspoken aggression to surreptitious affair this book has all the secrecy. Doubtless resulting from the system of reputation to which the neighbors all adhere, the Wellwoods neighborhood is a place of constant secrets. Everyone is afraid of their dirty laundry being found and aired before the rest of their neighbors. Secrecy abounds in the network in the form of gossip, closed doors, and blackmail. In the Wellwood household, their main method of communication is nothing; they don't talk about what's on their minds with one another. This leads to an entire mode of secret existence. When Humphry becomes jealous of Olive's success as an author, he bottles up his feelings and stops talking to her almost entirely. Although Olive notices the change, she too refuses to speak to him. They start to live in a mutually lonely world because of the weighty secrets they have to bear alone.
Jealousy
Interestingly enough, the jealousy element of this book is introduced through the character of Humphry. Ashamed that his wife makes more than him despite his important job, he becomes jealous of her accomplishments as an author. This jealousy leads him to behave in all sorts of nasty ways toward Olive, including having affairs with other women. While he actually desires his wife's attention, he is too much of a coward to talk to her; instead he chases every woman he can, looking for the love Olive doesn't give him. For her part, Olive becomes jealous of her sister. When she stops and looks up, she sees Violet mothering her children. True, she allowed this to happen, even invited Violet to come live with them, but she starts to resent her sister's popularity with the children. Olive loves her children, but she prioritizes her work higher, so it's particularly difficult for her to watch Tom and the others fawn over Violet. This is especially upsetting to Olive since she has convinced herself that publishing her books is the best way to support her children. If she stopped worrying about Violet, Olive may discover that the kids really would prefer for her to just spend more time with the instead of writing.
Reputation
Most of the characters of the book seem to set great stock in preserving their favorable reputations. In the Wellwoods' neighborhood, the neighbors make a practice of competition. They hold dinners and teas and all kinds of gatherings in order to show off for one another. As a particularly artistic community, most of the adults are home during the day. This opens the Wellwoods up to public criticism. In fact Olive stakes a great deal of her career upon reputation. People buy her books because they've heard of her as a children's author and a mother. Little do they know how absent of a mother she is, but she keeps up appearances for this very reason. She's often harsh on the kids because she wants them to make a good impression on people. Similarly, Humphry cares about his reputation. Throughout his numerous romantic relationships he maintains discretion in order to protect his job at the bank - a very prestigious position which requires a spotless record - and to ensure nobody informs his wife of his unfaithfulness. The kids and Violet are less susceptible to this push for reputation simply because they spend most of their time with each other at Todefright.