Tara Road by Meave Binchi

After being in a loveless relationship for so long, Irish woman, Ria Lynch, is desperately trying to save her marriage. She soon decides that another baby for them would solve their marital problems. Before Ria gets pregnant, Ria finds out that her husband had an affair with another woman and is the father of her child. Ria then decides to go away from her problems and switch houses with a woman in America.