Can’t stop thinking about my ex

We dated for 11 months and broke up 3 years ago. Only stopped contact with him 5 months ago. Logically he’s not the type of person I want to date nor do I want to be with him. I miss him though. I don’t know why I miss him because i don’t want him. I can’t stop thinking about him. I do love him and I don’t know why. It’s driving me crazy.