I just saw this at the Seattle Film Festival, Peter Saarsgard was there to answer questions. The movie is extremely watchable for the first half of the way through, is built on a fascinating premise with interesting characters (a bisexual movie producer and his wife who reside in a Lifestyles of the Rich And Famous type beachside modern mansion, a young gay writer whose lover has died of AIDS), and builds to a pitch of extreme suspense. After that, however, the plot stumbles and the film's conclusion turns on a series of unbelievable events. I thought since the movie was based on a play, the plot would be clear, but it's almost as if the movie version was forced to cut out some important sequences, as there is never quite enough information about 1) how the woman obtains all her inside information on the writer, 2) how the writer's ex-wife was related to the characters and 3) most importantly, what happens to the characters at the end of the movie.
I went into the bathroom after the movie and joined a lineup of women who were also asking each, "What exactly happened there?" --- when it's not clear it's a sign of unclear movie-making.