There's a trend in the amount of years of separation of couples on LOST, and that is, when one is on the island and the counterpart is somewhere out in the "real world", it's usually for a period of three years. Sun and Jin, Sawyer and Kate, Desmond and Penny. See how that works out? These three, at least in my view, have represented the doomed loves on LOST...and there's nothing like doomed love.
But of course, any true fan knows that Des and Pen were actually separated for eight years, with only three of those years belonging to island-time. Even with all the time-travel induced trauma on their relationship, these two still manage to be epic as ever.
Now it isn't known if Jacob ever made an appearance in either of these people's lives, but just because he didn't doesn't mean they weren't fated to be together. They are very much a mythology couple. Don't forget that Penny's father is Charles Widmore, former island guardian and partner to Eloise Hawking, time travel cop. Time has affected Desmond at every turn, and this made him central to the story from the moment we met him. But while he is "uniquely and miraculously special", he's nothing without his love.
Glad to be back home from my trip, and right on time! Just one more day to the premiere.