I suspect he was chronically depressed ; in psychiatry we call it “ Dysthymia”. Nothing really helps ; not meds or therapy . He was aging and was not adjusting well to it ,then his GF was in Rome ( where she lives ) photographed hugging and kissing another man. They can say all they want that she and Bourdain had an “ Open Relationship” but he had stated that he had never loved “anyone” , the way he loved her. Add that altogether and I think there were reasons :-(