Toby and Kate Aren't Together Anymore
On the flip side, Toby isn't wearing his wedding ring in the flash-forward. There could be two reasons for that, and neither of them are good. For one, Toby and Kate could be divorced in the flash-forward. During Toby's phone call with Randall, he asks if "she" would want him to be there. While we initially thought he was referencing Rebecca, he could be talking about Kate. Even though they aren't together anymore, Kate might still want his support as she goes to visit her mom. Especially if they do share a child together in the flash-forward.
Another reason Toby isn't wearing his wedding ring could be that Kate isn't alive in the flash-forward. In the episode "The Graduates," Kate is rushed to the emergency room after going into labor early. Some fans suspect that there will be complications and Kate will die giving birth.