He may or may not change his mind, but it is best to let him go if that is what he truly wants. You really wouldn't want to pursue something that he is not sure about then 10 years from now have him separate from you. It would then be much more difficult for him to move on. Even though it may be hard for you now it may be the best thing for both of you. Just be his friend and see what happens if it is meant to be it will be. I wish you all the best!