This was not at all the film I thought I was signing up for. Fortunately I really liked the film it turned out to be.
Judging by the synopsis here and the trailer it looked like:
"I have just discovered something horrible about my husband so I snap and kill him"
That's not what this film is at all. It is more:
"I have a complex history and a complex relationship which leads to murder"
Calling this film a comedy is also WAY off the mark. The very small, very brief bits of jet black comedy are completely drowned out by the uncomfortable darkness. Ultimately this film is a tragedy and you have to accept that going in.
This reminded me strongly of Marjane Satrapi's 'The Voices' with a hint of Cory Finley's 'Thoroughbreds' (Both excellent films BTW). From the very opening shot the mental state of the protagonist is in question and the way the film plays out from that point doesn't have too many surprises, but it's superb nonetheless. Sarah Roy in particular puts in sterling work.
Accept this as an uncomfortable tragedy rather than a black comedy and I think it's well worth watching.