missing my ex

lately I'm thinking about my ex a lot. we broke up because it just did not fit and he didn't want to stay friends. now I'm missing talking to him or just asking how he is. I mean, I love my current boyfriend deeply and would never cheat on him, I just would like to talk to my ex. but he said when we broke up he don't want contact to his ex's and I want to respect that. what can I do to stop thinking about that? edit: we broke up because we were in a long distance relationship and both weren't able to commit out whole weekends to each other.