Long shot, I read a book about 3 years ago and would love to read it again. The bits I can remember are;
The story is told from the point of view of a girl paralyzed from fall from the family home, only find out at the end.
The majority is set in the large family home, possibly a castle type place.
There is an artist living in his studio in the grounds of the family home.
One of the sisters has an illicit relationship with the artist.
There is a sex scene in a cupboard.
One of the sisters at the end moves to Africa, and from what i can remember develops cancer.
I'm sure it's a really well known book, does any one recognise it?