Are you completely sure that he actually means what he said, that he would choose his career over you? In practice, i think he would find that difficult, especially since you have been together so long.
And as for "careers are life, relaitionships are not" speak, then i'm afraid i am going to have to disagree with that. Careers are important. So are relationships. If you really love someone, you have to reach a compromise.
You can't just let one superceed the other. I really do have a lot of sympathy for you, and it's not as clear cut as everyone is saying.
Can you not stay together and weather the distance?I know it's easier said than done, but i'm in a long distance relaitionship and we are extremely close. It is a test but rewarding, we can tell each other anything and everything-and at the beginning we had to, otherwise it wouldn't have worked out. Now we do because we want to.We speak every day and see each other roughly every two weeks.
It's not ideal, but we know it's worth it. I really wish you the best of luck; i hope you can reach a compromise and work something out. At the end of the day you can't stop him though. Supporting him maybe the thing that draws you even closer, he will realise you and your understanding is invaluable.