The actress, 32, died on 20 December (09) after suffering a cardiac arrest at her Hollywood Hills home. She was laid to rest on Christmas Eve (24Dec09), but the cause of her death has been deferred pending toxicology results.
Monjack and his mother-in-law Sharon have now spoken out for an upcoming U.S. chat show - and the British director is convinced the Tinseltown lifestyle led to his wife's death.
In an emotional interview with Larry King, he says: "You want to know what broke Brittany Murphy's heart? Hollywood broke Brittany Murphy's heart."
Monjack also speaks frankly in the TV chat about how he and Sharon are dealing with the death of the young actress.
He says, "I don't think I am. I don't think either of us are (coping). You wake up in the morning and it's like a rebirth. It's - there's not enough time to - your dreams, be they good or bad, when you wake up and I reach out to touch or hold my wife and she isn't there."
The heartbroken pair also opens up about the moment they learned Murphy was dead.
Monjack tells King that doctors let him and his mother-in-law hear the tragic news at the same time - but Sharon is adamant she knew her beloved daughter had died before she was told.
She says, "We knew before that. It was just - you know, you felt her life go out of her."
The interview is set to be broadcast in the U.S. on Wednesday (20Jan10).