If you haven't seen this meme, then I'm not sure where you've been because ideas have been swirling about Jack and Rose and the door that led to his eventual death.
BUT... people seem to fail to remember that there's a lot more to consider with a plank of wood than just rearranging a few people. BUOYANCY PEOPLE! Open your eyes... there is no way Leo and Kate could both have fit on the door and it could have floated as well. That's not realistic - and really, it's not that romantic either. Look at the middle row picture on the right... sink much?
RIP Jack Dawson