Time travel to the past has created a doppelganger in our story!
Justin Kennedy meets himself, we'll call him JJ. JJ is in far better shape that Justin as he has not under gone the tragedies that have befallen his older self.
Ah, Justin has just met up again with his wife, Angela, who is pregnant and will die in a plane crash in a few short weeks if he cannot stop it from happening. He is unwilling to worry her so he states that he came "back to the past" to share medical advances that will help everyone. Stay tuned, the characters are now in charge once more.
The split-in-time scenario has not occurred as yet as nothing had really changed the past yet, just effected it. But when, (or if) the past is changed, things will become problematic for everyone.