Something Borrowed by Emily Giffin
Starts out with young teens looking up the date of their 30th birthdays.
Then they are in their late 20's and they have no idea where they are going or what they will be doing.
They grew up together, right next door to one another and did everything together.
Years later: Darcy is to be married and they all go out drinking, problem is Rachel is so drunk she goes to bed with Darcy's boyfriend, Dexter and
it doesn't stop there. Seems he wants to know her better than worry about marrying Darcy.
There are many relationships they each go through and hope they've made the right decisions.
Love trip to England and the castles sound gorgeous.