I'm going to try and explain this as clearly as I can...


It was revealed that the shape shifters only begin shifting when vampires are around, and as long as the shifting gene is active, they stop aging. (They accelerate in age until they reach full size, then stop until all the vampires are away)
With Jacob and Renesmee's connection, it can be concluded that Jacob will now be forced to continue shifting and never age again.

I am assuming that Renesmee won't cause Jacob to stop aging, but I really don't know. I'm wondering what everyone thinks would happen with Jacob and the rest of the pack.

It's a complicated dynamic.
If The Cullens remained close to the reservation, all the shifters would probably stop aging, but that wouldn't stop later generations from shifting as well.
If anyone in the pack has any children, they'll begin shifting when old enough, then rapidly age to catch up with their fathers, then stop aging as well.
Imagine a whole tribe of people where all the males are seven feet tall, buff-looking and appear no older than 25.

There's the possibility that Jacob would leave the pack, his family, and his friends, so they could continue on normally.


I think it's an interesting dynamic...

I hope i'm making sense here.

You made yourself pretty clear

This would make as an interesting story yet, I'd much rather have them not together. I was liking the Jacob and Leah thing going on :(

Though I think they wouldn't spend all their time with the Cullen.

I always interpreted the vampire presence shifting trigger as what initially forces a werewolf to shift, not that the presence of vampires (particularly ones they're familiar with and know aren't a threat to humans, like the Cullens) will continually force a werewolf to keep shifting. Once they've gained control, the werewolves can choose whether or not to shift, though they can also do so accidentally if they lose their temper enough or feel threatened. Similarly, I believe a werewolf once activated could still keep shifting without a vampire near.

However, the Cullens would still need to leave the area eventually, before the humans notice their lack of ageing. Jacob would follow because the imprint would cause him pain to be separated from Nessie. I also believe that possibly the Cullens could choose to avoid Forks in future, in order to avoid triggering future generations.