Read it through once

"Ah, Monsieur, if I could tell you!" M. Rivière paused. "_Tenez_--the discovery, I suppose, of what I'd never thought of before: that she's an American. And that if you're an American of _her_ kind--of your kind--things that are accepted in certain other societies, or at least put up with as part of a general convenient give-and-take--become unthinkable, simply unthinkable. If Madame Olenska's relations understood what these things were, their opposition to her returning would no doubt be as unconditional as her own; but they seem to regard her husband's wish to have her back as proof of an irresistible longing for domestic life." M. Rivière paused, and then added: "Whereas it's far from being as simple as that."