The speaker wakes up to a beautiful morning and is immediately hurt by it. The sunlight, the soft sounds and the birdsong bring back a memory of being close to someone under the branches, touching their skin. The memory is sweet, but it carries pain. The image of poison mixed with pollen suggests that love and harm were tangled together, and the flowers picked for the loved one's hair are already doomed to wither.
In the second half, the tone turns more direct. The speaker says the past won't leave "with the grace of living things", meaning it refuses to fade the way a flower does. Regret is defined plainly: never forgetting, and always imagining the other lives that might have been. The repeated "to touch, briefly, your skin" returns at the end with a new weight: "for the last time." The mood is quiet, tender and mournful, a goodbye that the speaker can't quite finish.