Jacob always says that Bella wouldn't have to give anything up (eg: humanity) によって being with him but as he doesn't age wouldn't they be faced with the age dilemma again?
And Jacob would stay sixteen (or twenty five, if あなた prefer, as his body is already quite advanced) and Bella would be about eighty. And he can't bite her and have her turn into a werewolf, can he? So wouldn't she be better off with Edward so there wasn't a huge age difference and it wouldn't be creepy and weird?
XOXO Team Rosalie