Celestie777's poem is a list of the small and large sacrifices that come with loving someone who gives nothing in return. The speaker names these one after another: staying kind to a person who shows only their worst side, crying silently, and putting someone else first when they would never do the same. The repeated "To..." openings make it feel like a weight being added to, line by line.
The speaker feels exhausted, hurt, and a little bitter. Phrases like "give heaven to the devil" and "a restricted throat" show how much love has cost them, including their own voice and self-respect. Yet the ending shifts the tone. The speaker admits this may be "a grave mistake," then falls back on fate, saying they are not ruled by their heart or the other person's mind. It sounds like acceptance, though it could also be a way of coping with a choice that keeps hurting. The mood is heavy, sad, and quietly resigned.