As stated, Valancy's mother Amelia hasn't changed: she's still the bone-selfish, dim-witted cold fish that she's always been. Still bearing a grudge over Valancy having defied her and made the family the subject of gossip in town, Amelia's inclination is to behave with offended majesty toward her prodigal daughter. Uncle Ben however, though also selfish to the core, possesses a good deal more sense... or at least a sense of which side the bread is buttered on. To shun a disgraced family member and her reprobate husband is one thing, to cut off the wife of the sole heir to a multi million dollar fortune- and an internationally acclaimed author, to boot- would be an act of unmitigated folly. When Amelia says doubtfully that she supposes that they'll have to forgive Valancy, Uncle Benjamin looks at her incredulously and, proving that he's not completely without self-awareness, says that the real question is: will Snaith forgive them. He obviously knows that the entire Stirling clan- minus Cousin Georgina- has treated the couple badly and, while Valancy can no doubt be convinced to overlook their behaviour out of a sense of filial duty, Barney is unlikely to be so moved. It's clear Uncle Benjamin knows that some fence mending will need to be done and already we can see the narrative changing. Valancy now isn't a simple-minded girl who lost her mind and/or her morals; she's a clever and spirited woman who was held back and hemmed in by her stodgy mother until she finally snapped. Also, Barney's lifestyle wasn't that of a sinister criminal in hiding, but of an eccentric genius. He, Benjamin, can't understand why anyone would listen to a bunch of idle gossipers spinning such malicious tales. In a burst of avuncular affection which we've never seen him display before, he advises Amelia to treat Valancy with kindness and understanding.
Valancy meanwhile is too miserable to care how she is treated by her relations... all she can think about is how trapped Barney must now feel in their marriage, and how painfully empty her life will be without him. Her sense of self-worth, which was never strong thanks to her idiot family but had gradually been building over her months with Barney, has now completely crumbled. It doesn't even occur to her that Barney might not want a divorce- how could he not? In stark contrast with the rest of the Stirlings, Valancy behaves completely unselfishly, willing to sacrifice any chance of personal happiness to free Barney so that he can return to the life she's convinced he wants and deserves.