You have any other snakes (females) around him? If nothing has changed with his husbandry and his set up is the same I wouldn't imagine it's his care taking. I have had males (breeding size) get a little spun up when breeding season comes around but never go off food. Most of the time they just turn into bulldozers and re-arrange their set up. If the snake has good weight, I would just let him be and try and feed him every week as usual..