The Apparition- John Donne

In The Apparition by John Donne, the ghost says to her that he will not now reveal lest his telling it "preserve" her that he loves her. We now this when he says "... and since my love is spent... (Donne, 890)." He knows that he loves her now but he did not know this before she left him to be with another man. He knows that he will never be able to tell her and that she will not really care. He threatens her in this way in order to make himself feel better. He wants to think that she will care for him if she knows this. On the other hand, he might also be saying all of this because he knows she will never find out. He is sure that he can let out all his feelings without her ever finding out that he said them. I believe that either way, he is letting off his steam because he is angry that she left him to be with another man (as I am sure a lot of people would be in this situation). The sad thing is, the woman remains innocent because she does not know that he loves her.