The speaker admits a kind of failure: they are not good at touching. Instead of physical closeness, they seem to have been "spoiled" by "the instruments of love," a phrase that could point to music, books, or any tool that stands in for real contact. Love arrives secondhand, which fits the title, "Vicarious," meaning experienced through someone or something else.
The first line, "writing I have not," can be read two ways. It may be the start of a thought about writing, or it may be a confession that fuses writing with the rest of the sentence. That small ambiguity suggests the speaker is more at home on the page than in a person's arms.
The last stanza shifts to a quieter scene: reading music in bed. The phrase "leaden tumult" is striking, since it joins heaviness with noise. Judging by the imagery, the speaker feels deep emotion but also weariness and distance. The mood is lonely and reflective, with a dry, self-aware ache beneath it.