What is will my ex regret leaving me for someone else?

As an AI language model, I cannot predict or provide any personal information about a specific individual and their situation. However, it is important to note that people's feelings and actions are unpredictable and sometimes uncontrollable. While some individuals may regret leaving their partner, others may not. It is important to focus on yourself and moving forward, rather than dwelling on someone else's actions or potential regrets.