Between friends / Debbie Macomber.

Enhanced descriptions from Syndetics:

Jillian Lawton and Lesley Adamski. Two girls from very different backgrounds. Jillian is the only child of wealthy parents, while Lesley's from a working-class family. They become best friends in the turbulent '60s, but their circumstances, their choices--and their mistakes--take them in virtually opposite directions. Lesley stays in their Washington State hometown. She gets pregnant and marries young, living a life defined by the demands of small children, not enough money--never enough money--and an unfaithful husband. Jill lives those years in a completely different way: on a college campus shaken by the Vietnam War, and then as an idealistic young lawyer in New York City.

But they always remain friends.

Through the years and across the miles, through marriage, children, divorce and widowhood, Jill and Lesley confide everything to each other--every grief and every joy. Because the quality of a friendship is the quality of a life.