No real life similarities here, I'm simply pointing out that any outcome that reunites the MC and his ex is unworkable to the point of absolute absurdity.
The storyline here is not about a "friendly divorce", where both parents put the interests of their children first and try to isolate them from the conflicts inherent in any divorce. Mom prevented any communication between father and daughter. Lied to the daughter about the reason for the divorce. Attempted to use her as a pawn in her financial interest. Kidnapped her daughter and removed her from her ex-husband's country where the daughter was legally an adult. Showed no remorse until her daughter was removed from her custody and her life.
Any story requires a suspension of disbelief. Since the very beginning the MC has repeatedly affirmed that, while he had loved his ex, the relationship was over and he had no desire to ever be with her again. Given this foundation there is no possibility for them to reunite without shattering that suspension. Without a new path stretching back to the very beginning of the story, such an ending can't fit into the story.