Right before Sarah Stagg's teenage sons leave the nest, her husband, Andrew, the star of their local dramatic club, leaves her for his twentysomething leading lady, Hyacinth. Sarah, a freelance artist, quickly discovers that the path of a discarded wife is strewn with hazards and humiliations. Her neighbors and friends treat her like she has the plague. And her soon-to-be-ex wants to sell the house she's spent years turning into her dream home.

Her best friend Miriam offers one concrete piece of advice: Sarah should keep busy -- and with Andrew and Hyacinth on a sabbatical from their...