How to get over someone....

Ok so my problem is getting over a man that I fell in love with. We met in 2014 and its weird how we met. He's an exchange student from Germany and is training to be a pilot. He was here in the states for 2 months and I did t get to see him until the last 3 days he was here. We spent every hour together before he left. And we dated 4 months until we broke up. We talk but he was honest with me that he started talking to someone else and wanted me to know. I hated the idea of the man I love with someone. We would always end up fighting because of me not wanting him to be with her. But he tells me he still likes me and wants me apart of his life. I do still care about him but I want to be able to talk to him without getting jealous that he is with someone else. He says he wants me nothing but happy. But i was happy with him. How do I get over this feeling.... :( Help