The things left unsaid in The Age of Innocence

Writing about Jane Austen, Virginia Woolf ponders, if she had lived longer: 

“She would have devised a method, clear and composed as ever, but deeper and more suggestive, for conveying not only what people say, but what they leave unsaid; not only what they are, but (if we may be pardoned the vagueness of the expression) what life is.” (full essay)   

This is something I’ve noticed in The Age of Innocence: Edith Wharton writes a lot about things people leave unsaid.  
(From where we are, the 2 writers may not seem that far apart, at least to some of us, but more than 100 years passed between Jane Austen’s last novel, Persuasion, which was published in 1818, and The Age of Innocence, which was published in 1920, exactly 100 years ago). 
In The Age of Innocence, I think there are 3 main kinds of silence: 
1/ As Edith Wharton focuses on Newland Archer’s perspective (instead of switching between perspectives as she does in The Custom of the Country or The House of Mirth), such moments are about him—we know the things he thinks but doesn’t say. 
Newland has a gentleman’s restraint. For example, look at this exchange between him and his sister Janey: 

“"Not the half of one—if she thinks such old maid's rubbish."
"Mother is not an old maid," said his virgin sister with pinched lips.
He felt like shouting back: "Yes, she is, and so are the van der Luydens, and so we all are, when it comes to being so much as brushed by the wing-tip of Reality." But he saw her long gentle face puckering into tears, and felt ashamed of the useless pain he was inflicting.” (Ch.10)

 As he’s a gentleman, bound by conventions, there is lots of restraint in his conversations with Ellen Olenska. For example, this is when he and Ellen discuss her intention to file for divorce: 

“It was on his lips to exclaim: "My poor child—far more harm than anywhere else!" Instead, he answered, in a voice that sounded in his ears like Mr. Letterblair's: "New York society is a very small world compared with the one you've lived in. And it's ruled, in spite of appearances, by a few people with—well, rather old-fashioned ideas."” (Ch.12) 

Then: 

“"And you take their view?"
He stood up at this, wandered across the room, stared with void eyes at one of the pictures against the old red damask, and came back irresolutely to her side. How could he say: "Yes, if what your husband hints is true, or if you've no way of disproving it?"
"Sincerely—" she interjected, as he was about to speak.” (ibid.)   

He cannot bring himself to ask if she’s involved with her husband’s secretary, as her husband threatens to bring against her in the divorce. 

“Since she would not or could not say the one word that would have cleared the air, his wish was not to let her feel that he was trying to probe into her secret. Better keep on the surface, in the prudent old New York way, than risk uncovering a wound he could not heal.” (ibid.) 

As they both leave things unsaid, especially on Newland’s side, they keep the discussion on the surface and make assumptions about each other, and end up misunderstanding each other. In the end, Ellen chooses not to have a divorce, to protect him, May, and their families, and they cannot be together. 
There are many more such moments in The Age of Innocence. Newland may see all the conventions and restrictions in his society, but he too is part of society—he too has been brought up that way. He also chooses restraint and leaves thing unsaid, he also hints or avoids subjects instead of speaking frankly, he also keeps things on the surface, he also uses stock phrases like everyone else. He is exactly like the people he secretly condemns. 
However, this makes it so good when he confesses his feelings to Ellen. There is lots of passion, and a real sense of release.  
Later on, Newland, now married, still has restraint when seeing Ellen. Here is the scene in Boston: 

“The young man's blush deepened. She had pronounced the word as if it had no more significance than any other in her vocabulary. For a moment it was on the tip of his tongue to ask: "Did he send his secretary, then?" But the remembrance of Count Olenski's only letter to his wife was too present to him. He paused again, and then took another plunge.
"And the person?"— ” (Ch.23) 

A bit later: 

“They sat silent, not looking at each other, but straight ahead at the people passing along the path. Finally she turned her eyes again to his face and said: "You're not changed."
He felt like answering: "I was, till I saw you again;" but instead he stood up abruptly and glanced about him at the untidy sweltering park.” (ibid.) 

There he’s repressing his passion. It is no use. He’s now married. Anything with her is impossible. 

2/ The 2nd kind of silence is the silence of nearness and understanding, between Newland and Ellen—it is enough to be near each other, they do not speak. 

“As the paddle-wheels began to turn, and wharves and shipping to recede through the veil of heat, it seemed to Archer that everything in the old familiar world of habit was receding also. He longed to ask Madame Olenska if she did not have the same feeling: the feeling that they were starting on some long voyage from which they might never return. But he was afraid to say it, or anything else that might disturb the delicate balance of her trust in him. In reality he had no wish to betray that trust. There had been days and nights when the memory of their kiss had burned and burned on his lips; the day before even, on the drive to Portsmouth, the thought of her had run through him like fire; but now that she was beside him, and they were drifting forth into this unknown world, they seemed to have reached the kind of deeper nearness that a touch may sunder.” (ibid.) 

Later: 

“"And that's to be all—for either of us?"
"Well; it is all, isn't it?"
At that he sprang up, forgetting everything but the sweetness of her face. She rose too, not as if to meet him or to flee from him, but quietly, as though the worst of the task were done and she had only to wait; so quietly that, as he came close, her outstretched hands acted not as a check but as a guide to him. They fell into his, while her arms, extended but not rigid, kept him far enough off to let her surrendered face say the rest.
They may have stood in that way for a long time, or only for a few moments; but it was long enough for her silence to communicate all she had to say, and for him to feel that only one thing mattered. He must do nothing to make this meeting their last; he must leave their future in her care, asking only that she should keep fast hold of it.” (Ch.24) 

This is a magnificent scene. Newland and Ellen understand each other without speaking, they don’t need to say a word. They just stand there, in the moment. 

3/ The 3rd kind of silence, which I find particularly interesting, is May’s silence.  
Wharton does something interesting when she chooses to focus on Newland’s perspective, instead of switching between different points of view. We know what he thinks, we can guess what Ellen thinks, but what about May? How much does she know? 
Through Newland’s eyes, Wharton creates the impression that May is young, inexperienced, conventional, narrow, pure, and innocent—a nice girl, basically. But at the same time, we can see that May is not really what he thinks she is.  
Take this passage: 

“His wise May—how he had loved her for that letter! But he had not meant to act on it; he was too busy, to begin with, and he did not care, as an engaged man, to play too conspicuously the part of Madame Olenska's champion. He had an idea that she knew how to take care of herself a good deal better than the ingenuous May imagined. She had Beaufort at her feet, Mr. van der Luyden hovering above her like a protecting deity, and any number of candidates (Lawrence Lefferts among them) waiting their opportunity in the middle distance. Yet he never saw her, or exchanged a word with her, without feeling that, after all, May's ingenuousness almost amounted to a gift of divination. Ellen Olenska was lonely and she was unhappy.” (Ch.13) 

May has a sensitivity and perceptiveness that Newland doesn’t realise she has. She’s not naïve and ignorant either—he thinks nothing reaches her, but for a long time she knows about his previous affair with Mrs Rushworth, she just doesn’t ask about it.  
In this aspect, Newland is reminiscent of Ralph Marvell in The Custom of the Country—he looks down on his wife and underestimates her. 
To me, it’s obvious that May knows Newland’s involved with Ellen. When he speaks of going to Boston for business, it’s not stated in the novel but it should be easy for her to know that Ellen would also be there, as they’re cousins.  
The whole thing about the trip to Washington makes it even clearer, to the reader though not to Newland, that she knows. When he mentions the trip the 1st time, she tells him to remember to visit Ellen, I suppose, to see his reaction, and to let him know that she knows he lies. When their grandmother Mrs Manson Mingott has a stroke and wants Ellen back, the way May mentions Newland’s Washington business trip, in front of everybody, shows her cunning. They would cross paths. 
Later on, when the Wellands argue about who should pick up Ellen, and Newland volunteers, it seems obvious that May has been waiting to see what he says, then she acts like it’s all good, to keep up the happy couple image in front of her parents. But afterwards, she cross-examines Newland about why his employer (Mr Letterblair) goes to Washington but he doesn’t. 
I’ve written enough. May is no simpleton, and her silence is much more interesting as Wharton hints that she knows a lot more than she shows.