I am trying to remember the title of a novel that was most likely written in the 1980s. I read it in in 7th grade (1992-93). It was about three girls who all became friends at a boarding school and follows them into adulthood. The main character was from a poor family and she received a scholarship to go to the boarding school. Her younger sister married a rock musician while still a teenager and went on to have a hard life. After boarding school the main character moved to New York and became a personal assistant and got married then divorced. One of the girls was named Allie and she was from a very rich family and never had to work. She slept with one of the other girl’s father and the husband of the main character. I don’t really remember much about the third girl. I can’t remember of the other characters names or any hint of the title. This has been driving me crazy!!
Bit of a long shot, but there’s some overlap here with Garret Weyr’s ‘Pretty Girls’ (1988).
This reminds me strongly of Adele Geras’s Egerton Hall novels, the first of which is “The Tower Room”, which is on Google Books.
https://books.google.co.uk/books?id=1CmLBOhger0C&lpg=PP1&dq=the%20egerton%20hall%20novels&pg=PT7#v=onepage&q=the%20egerton%20hall%20novels&f=false