Originally Posted by Ikarus
Here's a theory: since we haven't seen Jack's wife yet, it could be anyone. What if it's Kate who's leading a double life and in one life she is a fugitive because of a crime she didn't commit and in the other she's Jack's ex-wife and that's why he gave her that strange look back at the airport in episode 3. Try to beat that in crazy!
I am pretty sure that Kate is the wife of Jack and David is their son at the end. Kate and Jack are divorced or separated... I think Jack and Kate belong together but Kate and Jack has some issues to work out. At the end I believe they will be together and Jack loves his son. Jack doesn't want the relationship with his son that Jack had with his dad...and in this last episode it shows the love he has for his son. This is what Jacob wants for Jack. Down the road Kate will realize also how important her life is with Jack as well.