Love lives in those who are willing to make the greatest sacrifices without keeping account.
Saying good bye to the one you love has to be the hardest thing there is, whether it is a temporary farewell or one that could be permanent. Diana always gave Clark strength to face whatever he had to whenever they parted. There was never any protestations for self preservation nor to have him remain for her sake. No histrionics for him not to go face danger when the job called for hard decisions. She even threw herself in danger as well because the world always came first. She understood that he did not belong to her alone and that he should never be put in a position to want to put her safety above everything or everyone. Theirs is a selfless love that maintains their principles as heroes. And when she faced losing him forever, despite her heart breaking, she gave him courage and strength to go and be at peace. THIS is real love.