Since Natalie Portman confirmed that she won't return as Jane Foster in Thor: Ragnarok, we’ve been wondering how Marvel Studios would explain the character's absence. Thanks to Entertainment Weekly, we finally have an answer.
Marvel told EW that the extremely long-distance relationship between the astrophysicist and the Norse God of Thunder had come to an end. The two must have broken up sometime between the events of Avengers: Age of Ultron and Thor: Ragnarok.
Portman's character didn't show up in the Joss Whedon flick, but it was mentioned that she’d been carrying out research in her field that led to her becoming a potential candidate for a Nobel Prize. In the upcoming Taika Waititi flick, Thor has changed significantly since he left Earth to find answers to his questions regarding the Infinity Stones and the mysterious entity manipulating the Avengers. According to Chris Hemsworth:
He's off exploring the universe, still trying to police it and control the mayhem. But he's certainly enjoying being a drifter, being a solo cowboy out there.
Marvel also used the break-up excuse for the absence of Gwyneth Paltrow's Pepper Potts, the love interest of Robert Downey Jr.'s Tony Stark, in last year's Captain America: Civil War. But while Tony has yet to find a new inamorata, Thor seems to have done so with Valkyrie (Tessa Thompson). Marvel President Kevin Feige said:
We wanted Thor to encounter somebody that was near his equal and that his relationship with Jane may have evolved in unexpected ways in between The Dark World and Ragnarok and we wanted to pit him against a character who was much more his equal and in many ways his superior. Valkyrie is trying to not embrace any sort of Asgardian heritage that she has. Thor thinks maybe that will create a bond between them and, on the contrary, she wants to forget it all entirely.