My boyfriend wants to chummy with his friend but i don't. How can i convince him to chummy only the 2 of us?

You need to plan your future and quit worrying about what he is doing. Evidently he is satisfied with the way things are. Make your plans to go to another country and have a wonderful time while you are young. You will not regret it. Do not depend on anyone to make you happy. You must make yourself happy. Don't waste the next two years planning something that is unlikely to happen and fretting over the situation.