Is what a husband tells his wife about problems with his first wife, and the subsequent anxiety and excessive rumination about interpreting his words and the possibility of them being a hint or a choice for divorce, considered a delusion or a reality?

You must ignore the whispers of divorce or anything else, and not ask your husband about his intention regarding what you imagine to be words or allusions of divorce. One of the greatest aids in getting rid of obsessive thoughts is to seek Allah’s help, sincerely turn to Him, and supplicate frequently.