I've been reading more thrillers and chick-lit sorts of books than I ever have before, and so now after reading maybe half a dozen volumes of "current popular fiction,' I am now an expert. "The Other Woman" combines the ultra-refined, genteel, upper-middle-class tone of the wonderful chick-lit book "How Hard Can It Be?" by Allison Pearson with a bit of the psychological horror and terror of "The Last Mrs. Parrish" by Liv Constantine.
I sort of predicted/expected the first couple revelations because they were advertised well in advance, and when those came up, the other, final Big Revelation was hinted at, so I kind of expected that, too. But it was such a delight enjoying these characters and the machinations of the plot, that I must recommend this!
And I'm glad this isn't as scary as "The Last Mrs. Parrish"!