We have been dating for over a year, and we have been through a lot together. He is 22 and I am 18. He is ready to marry me and settle down, but I know I am way too young. He is insecure in our relationship, always saying how pretty I am and how I am too good for him.
I am leaving for college this week where I will live 4 hours away while he stays in our hometown. I have always been a little bit of a drifter and value my freedom. I'm afraid of missing out on my college experience by being tied down with a clingy boyfriend.
How can I break up with him without breaking his heart? I really care about him and want him to be happy, but not at the expense of my happiness. Please help me.

There is no way to break up with someone without breaking their heart if they are in love with you. But it is even worse for you to lead him on whenever you are wanting to enjoy your college experience. Tell him the truth, he is just going to have to understand. Which he will, and he will move on from this relationship eventually.