Does the Narcissist ever come to idealise his previously discarded source even though they're no longer around and he has other sources?

Yes, a narcissist can idealize a previously discarded source, even after moving on to other sources. This tendency often stems from their need for validation and control, leading them to romanticize past relationships when they feel insecure or threatened. The idealization can be a way to maintain a sense of superiority or to manipulate others by invoking jealousy. Ultimately, this behavior reflects their unstable self-esteem rather than genuine affection for the discarded source.