The House on the Borderland by William Hope Hodgson

How long our souls lay in the arms of joy, I cannot say; but, all at once, I was waked from my happiness by a diminution of the pale and gentle light that lit the Sea of Sleep. I turned toward the huge, white orb, with a premonition of coming trouble. One side of it was curving inward, as though a convex, black shadow were sweeping across it. My memory went back. It was thus, that the darkness had come, before our last parting. I turned toward my Love, inquiringly. With a sudden knowledge of woe, I noticed how wan and unreal she had grown, even in that brief space. Her voice seemed to come to me from a distance. The touch of her hands was no more than the gentle pressure of a summer wind, and grew less perceptible.

Already, quite half of the immense globe was shrouded. A feeling of desperation seized me. Was she about to leave me? Would she have to go, as she had gone before? I questioned her, anxiously, frightenedly; and she, nestling closer, explained, in that strange, faraway voice, that it was imperative she should leave me, before the Sun of Darkness -- as she termed it -- blotted out the light. At this confirmation of my fears, I was overcome with despair; and could only look, voicelessly, across the quiet plains of the silent sea.