Martha and Jack will always be one of those special couples.
It wasn't that they had a relationship broke off and then got together again. Even when they were not together and had other partners, they kept on needing each other and turning to each other for support. This made me wanting them to be together so badly.
Other couples, when they seperate, they have not much in common anymore and few scenes together. By jack and martha, they ALWAYS had scenes together, for us to know that they wish to be together. That's why i love them together, and don't think anyone can replace Jack. Sure Martha will fall in love again, but nothing which can be compared to her feelings for Jack.
Must have been weird for Jodi, after so many scenes with Paul (and they had tons), not to have any single one anymore.