Do long distance relationships last?

My boyfriend is about to move to a different state for work. He'd be gone for two years at the most and would visit at least once every month or two. He says he'll never stop loving me and that he doesn't want this to be the end of us. I'm scared of him meeting someone else after a year, or at some point halfway through our separation. I want the best for him and I'd be happy if he found someone who makes him happy but I'd be annoyed at all the opportunities I missed while I was waiting for him to come back. I don't even know if what I just said makes sense but what do you guys think?