They never got back together.Zachary knew that she didn't him.Zachary knew has to get his revenge.He will make her jelouse by getting another girlfriend.
Alexa was just looking out for Zachary's feelings even if it means hurting him.She knows that she it will be better to hurt him for the last time than to hurt him every day of their lives.
They just have to forget everything about their relationship.They can never br back together.
