'cos if it's Jack that marries them, he knows there will be someone for a very, very, very long time, even long after he and Rose are gone, who will remember them and what they were to each other.

That’s very, very true (and something that I might put in a future fic of this set, because I get the strangest feeling that there’ll be more where this came from at some point).

I can’t help but think that that is probably quite a lot to do with his choice of Jack in the first place.