People please, if you look hard enough there are accounts of affairs and whatnot in that timeframe, of course it would me much rarer than now, but it was by no means impossible. To say it never happened back then is naive. Yes the Edwardian times were different, but that doesn't mean things like that never happened. Get over it.

Cameron needed two characters we could get attached to & feel the emotion of the tragedy through them. It would have been harder to get us to attached to real people in that same way being we do not know that much about a lot of the people's personal lives onboard.