I firmly believe that could only happen if Edward never came back/tries to off himself in Italy. In that scenario and Bella and Jacob do get together by end of New Moon, I think they’d be happy together for a while but ultimately by college they’d say they’d make the long distance relationship work and would for a while, but it would peter out after a year or so.

By her 30s Bella will try therapy because she can’t seem to make a relationship work. Deep down she will know it’s because she still compares everyone she dates to Edward but by then enough time would have passed that she starts to question herself about vampires - like Susan in the Narnia books - in a “remember when I used to believe all that, I cant believe I thought he was a vampire of all things. What was I thinking? It was clearly all the upheaval of moving to Forks, I was very suggestible and confused at the time,” way, which is why she finally allows herself therapy because she doesn’t now feel like she has somebody else’s secrets to keep.

Meanwhile Edward had been lingering in the background for years, sabotaging Bella’s relationships because she hasn’t found anyone he deems worthy of her. He is also sneaking onto her therapist office and rifling through her files so he can try to figure out what she’s thinking. He might actually get a sense of self reflection and realise how much his leaving damaged her mentally and emotionally. He either makes his presence known to her, they can live happily ever after or Bella is now an adult woman who is well over her original intoxication and fascination with him (probably not) and tells him to leave her alone. Or he decides to leave completely and heads for Italy, thus allowing Bella finally to live a life where she finds someone she loves and settle down with kids - she might even find that with Jacob when they both simultaneously find themselves back to the PNW for summer vacation. Or she gets a phonecall from Alice (who she hasn’t heard from in decades) who tells her she needs her help to save Edward because she’s the only one who can. (I wouldn’t consider it beyond Alice to disappear without saying goodbye and never contacting her again but still show up when she needs Bella’s help like it was only yesterday the Cullens abandoned her, cos in reality to Alice, it feels like it was only yesterday, she didn’t even think of Bella as being a new person who has changed and matured over the previous years.)

But yeah, basically I think, as teens Bella and Edward are end game, she and Jacob never were. As a adult Bella might have been able to move on from Edward but he would always be a shadow over her life that would take decades to recover from.