So why does he keep calling me. Yesterday he called me asked me if I found someone else and I told him no. He told me found some girl but I guess he is tired of her. I don't understand what is his purpose of keep calling me he should just leave me alone .What could he possibly want from me ? I am like 3 hours away from him

He is familiar with you. He is used to talking to you about these things. He wants to check in occasionally to make sure that his backstop, YOU, is still in place if he ever gets tired of looking for something better.

He wants something better (not that there is anything wrong with you, he just wants to see if he can do better) and is apparently trying. If that doesn't work out, you're his contingency.

Are you his option? You OK with that?

He calls you, reaches out, out of familiarity and habit. It's up to you to decide if that's OK. You know his intention now.