Here is my opinion, “I am terribly sorry. I know this isn’t what you want to hear but the simple fact is I don’t see a future for us. This may seem terribly selfish of me but in fact I am truly thinking of both of us. It simply isn’t fair to give you false hope that we will last forever when I have already decided this isn’t what I want. I know this hurts and for that I am sorry. But you deserve to be with someone who wants to be with you as much you want to be with them. I promise you, it was nothing you did or didn’t do, you don’t have to change anything about you. I simply don’t feel what I should feel and that isn’t fair to either of us. I wish you all the best and hope you find that special person.