The War of the Roses by Warren Adler

JONATHAN AND BARBARA ROSE ARE THE PERFECT COUPLE

. . . living the dream in their beautiful house, filled with their precious antiques, their darling children and their prized Ferrari. Surely, it's all anyone could possibly want?
But when Jonathan experiences a sudden heart attack (or so he thinks), Barbara realises that she wants a new life, without him. There's just one problem: they both want the house. For husband and wife, it's not just a residence: it's a passion, one that will provide the battlefield, complete with weapons and casualties, for the escalating war that follows.

In this vicious black comedy, the Roses will each do whatever they can to destroy their better half - no matter the cost to themselves . . .