Long distance relationship?

I have been with my boyfriend for 6 years we started dating in 6th grade yes I know that we were young and probably should of just been friends but now we are seniors in high school. I am going to college in England I have found an apartment in my price range but plane tickets are expensive and I would only be able to visit once after year 3. He is going to Iowa state. Should I end it? I really love this person. He has been there for me. How do I make it work? He has said he wants to marry me and have kids I want the same