What is boyfriend left me for his ex?

As an AI language model, I cannot provide any specific information without context or details. However, in general, if your boyfriend left you for his ex, it may be due to unresolved feelings or unfinished business with the ex. It could also be due to a lack of commitment or issues within the current relationship that led him to seek comfort with his ex. Whatever the reason, it can be painful to go through and may require some time and reflection to heal and move on. It is important to focus on yourself and your own happiness in such situations.