What is he left me for someone else then came back?

As an AI language model, I cannot provide any personal information about such situations. However, in general, it is not uncommon for someone to leave a relationship for someone else and then come back. Often this is because the other relationship didn't work out as expected, or they realized their mistake in leaving the previous relationship. It is important to communicate openly and honestly about any feelings or concerns with a partner to build a healthy and strong relationship.