Should i be worried that we won't ever get married?

My boyfriend and I have been dating for over a year and a half. He used to always tell me that he wanted to marry me, he told his friends one night that he was never the type to want to get married until he met me, etc. Recently, he told me he's not sure if he wants to get married. He's about to move out (into his own apartment, he lives with his parents right now, we don't live together), start his new stressful career as a police office. Could he be having second thoughts because of some of the big changes that are about to happen in his life? He said that its nothing I've ever done to him that has made him reconsider marriage because he loves and cares about me more than anyone he has ever been with but that its just not on his mind right now. I love him and want to marry him eventually but i'm worried that his changed mind will be changed forever. Could all of his marriage "fear" just be caused by his new job and new worries/stress he's about to face and the big changes he's about to go through?