It takes time mostly. What helps is traveling to and visiting a new location with friends. It doesn't have to be fancy, but it should be out of your normal stomping grounds - and it must be a shared experience with friends (or siblings).
If u truly live him it will take time! You didn't build a relationship overnight so u can't end one overnight! Don't leave urself open to him shut the door and nail it closed. Easier said than done but it will protect you