Coming at it from the opposite direction, isn't it strange how fans of a songwriter try to put together a biography of the artist from the songs?
The assumption is that all the first person songs relate actual experiences.
One of the writers whose work I love is Melanie (Safka). If everything in her songs had happened as described she would have had more lovers than Messalina and Catherine the Great put together! I know for a fact that she has been married to the same man since the sixties and they have brought up three children.
I do think that a song needs to be based on an emotional insight into the narrative, a grain of truth. Beyond that, the process of turning that into a piece of art involves polishing and adapting that grain into something that fits the dramatic structure of a song.
You start from observation, add a touch of "what if..." and after that it's a craft skill to build the song.