Just because you seem to attract your ex back, it doesn’t mean you are unable to attract the person you do want. And you don’t have to allow your ex into your life if you don’t want to. Have you been visualizing and living in the end of being in a relationship with the person you do want? If you’ve been doing that, you could be on your way to manifesting this person and your ex could just be feeling the new energy and thar’s why he returned. Don’t give up.