The Vine Of Desire by Chitra Banerjee Divakaruni

The beloved characters of Chitra Banerjee Divakaruni's bestselling novel Sister of My Heart
 
are reunited in this powerful narrative that challenges the emotional bond between two lifelong friends, as the husband of one becomes dangerously attracted to the other.
Anju and Sudha formed an astounding, almost psychic connection during their childhood in India. When Anju invites Sudha, a single mother in Calcutta, to come live with her and her husband, Sunil, in California, Sudha foolishly accepts, knowing full well that Sunil has long desired her. As Sunil's attraction rises to the surface, the trio must struggle to make sense of the freedoms of America-and of the ties that bind them to India and to one another.