Memory is the engine here. The speaker looks back on a lover and drifts between two seasons: cold December mornings and warm summer evenings. In the winter scene, the only desire is simple, to stay close to the other person's warmth. The wording "taste the memory" suggests the past is still vivid enough to feel physically present.
The second half shifts to summer and to watching rather than staying. The lover rises from bed "like a feline," and the speaker sees even a casual stretch as drawing "the most perfect lines," as if the body were making art. Sunlight moves from a halo to fingertips on skin, which gives the moment something close to reverence.
The mood is tender, intimate and quietly wistful. The opening "I remember…" and the fact that everything is past hint at absence, but the poem never says what happened. It simply holds onto these small, glowing moments.