My take on the movie Spoilers obviously
This movie may have a lot of layers, but the main story is pretty simple. Everything that is discussed is about the couple relation ship. Not only what is said, but when, to drive the story further.
The husband is a writer who has abandoned his dreams to write for the big money in the movie industry. This has led the couple to live the high life.
In order to maintain this life style and get a writing gig the husband pimps his wife to a movie producer. It upsets her and fills her with contempt for her man. However she is quite pragmatic and soon realises it doesn't bother her much as she wants to keep the the life style they have achieved.
Still there is something that bothers her, that she can't put her finger on. It is how cocky the husband is. He must think a lot of himself to let her go with a rich Hollywood movie producer and not even consider she may leave him for the producer. He couldn't possibly love her and do such a thing.
He on the other hand thinks that she is mad about the pimping, that he tries to justify to himself. He tries to figure out if this is the reason she is mad, all the while he pretends that he doesn't know that he made her sleep with him because he is ashamed of it.
In the end she decides to strike back at him, by leaving with the movie producer. As it is a tragedy, it doesn't end well. But then again I may be wrong.