Well, I'm not trying to offend you or make you mad. I'm just telling you what I know of the film.
In every peice of literature every printed about the film, Jack and Rose have been talked about as fictional. Mr. Cameron himself admited to that fact.
People who still think they were real people after the director of the film publically calling them fictional are just getting swept up in the romance of the movie.
Don't get me wrong, if there's a man out there like the guy in Phantom of the Opera, I'll easily divorce my current husband and marry the other man.. and my husband knows it...but it's just the romanticism of the film... that's why they do that.. it's all a ploy to rake in the money.. as Titanic clearly did, becoming the number one movie at the box office of all time.