What should I do?

My boyfriend and I have been together for about a year and a half now. He's graduating high school next month and I don't know what his intentions are with me. He's never made it entirely clear. I am hopelessly in love with him, and I cannot bear the thought of not being with him. He means a lot to me and I really want us to work out .. I don't want his love for me to die. I don't know how to handle the uncertainty though, I always need reassurance but he can't give me that. I don't know what the solution is. As of now I can't break up with him because I don't want to lose him but I don't know what else there is to do. Please help? Advice?