There was a period in the nineteenth centuries where American heiresses often married English lords. This book traces the progress, and how they found them, and what matrimony was like.
The very first marriages -- like that of Jennie Jerome and Lord Randolph Churchill -- were in fact of people who hadn't managed to break into society in New York City. The Knickerbockers were very strict and very stuffy and didn't approve of all this new money stuff. Why the newcomers would buy gowns by Worth from Paris -- and then wear them as soon as they passed customs! Instead of properly putting them in the closet to wear after a year or two. They found it easier on the other side of the Atlantic, where they actually met people instead of just seeing the sights. The English had their titles so the new blood couldn't rise too high, and besides, these American girls were charming! They hadn't been kept confined in the nursery but allowed to mix with boys even, so they were not tongue-tied at the dinner table. It grew steadily more accepted until you had a period where an American heiress could buy herself a titled (albeit impoverished) husband by right. The already wed heiresses provided an entry into society -- some of them even did it professionally.
Married life -- well, the servants were a shock. You had a lot more, but they were inflexible in their routines and fully aware of their prerogatives. The people attached to her estate were interested in her as the young lord's wife, not as herself. The houses were actually cold in the winter, and lacked plumbing. Her supreme duty, producing the heir and the spare, didn't mean she would have anything to do with the children once born.
On the other hand, she could have a much wider range outside the house. In New York City, of course, no one upper-crust would indulge in politics, but in England, the upper-crust was politics. She could be out there making speeches. And once she had produced the heir and the spare, there were properly discreet love affairs. It was unwise to comment on how a third or later child did not resemble the older ones. She could even live a life quite separate from her husband.
Some liked it, some did not. The fashion declined, after a time, but only after scads of marriages.