The Head of the House of Coombe by Frances Hodgson Burnett, Juvenile Fiction, Classics, Family

Amabel was born and raised in a large but poor household in the Channel Islands -- and her encountering Robert Gareth-Lawless of London seems a rare stroke of good fortune: for when are there ever enough eligible bachelors among these wave-washed villages? And she is to be carried off, to dine and dance with the well-to-do of that most brilliant of English cities!
Amabel, who takes on the nickname of Feather, loves the life she finds there -- even when less pleasant aspects of reality begin intruding. She learns that the Gareth-Lawless mode of high living is based not so much on property or wealth, but upon debt and keeping ahead of the creditors . . . and then learns she is pregnant.
Now Feather has come to the attention of the head of the House of Coombe -- a world-wise, witty man who shows great sensitivity in his own clothing, and a similarly great appreciation for what she has done for herself, in presenting herself to society. It is strange, to be receiving the attentions of so important a man. She wonders what this portends -- even as tragedy strikes her small household.