I'm in a similiar situation, I have an amazing boyfriend. I know what he would say, when I'm gone he wouldn't have viewed our relationship as a "waste". He'd treasure the memories. Each and every one of them, though he would feel pain, more pain than I think I can inflict on him. He's the type of person who is just happy and uplifting and brings light to everyone around him. What if I'm the one who extinguishes that light? I don't think I could ever forgive myself, not that I would have to. I guess my problems would likely end at that moment.
What a pickle we've gotten ourselves into isn't it? Having found love and been able to experience it and now we are faced with either eternal pain or possibly snuffing out the light of our loved one. Life's cruel in that way.