This is a rather different poem, describing the paradoxes of love for someone who doesn't love you. In contrast to the other poems, this poem is not written from the perspective of the poet, but describes a general mechanism. It may be a summary of the story in the whole cycle. But this is not necessarily the case.
The song is written in Es, the parallel of g minor in the song before. It starts just with I, V7, I, II7, V, I, which harmonic progression is repeated when the voice starts. In m. 10 the C7 chord is introduced, a VI in Es and solving towards the f chord in m. 11. At the end of m. 11 the C7 is repeated, but immediately jumps to Bes (skipping the step over f) that goes via Bes and Es finally in F, but an F7, that goes back to Bes, the new harmonic center. Or is f the center?
In m. 19 the c is defined as a IV in g, where we have the progression IV-V-I, which then transforms to a clear F progression in m. 22-24. (I-IV-V7-I-IV). The Bes becomes a Bes7 in m. 25.
Then we have a harmony that seems to be not very well defined. The voice suggests in m. 26 Es, followed by Bes in m. 27, but the Bes-As interval in the piano suggests more Bes in m. 26, while the E in m. 27 may be just a appoggiatura.
In m. 29 a Des7, followed by a Ges and a diminished chord on the first beat of m. 31 transforms finally back into the tonality Es in m. 32. The piano postlude starts with a II7-V7-I relationship and then finds its equilibrium in a IV-I-V-I. The conclusion is stated in m. 45-46 with very clear Es chords. Have a look at the melody in the first half and second half of the postlude. The center tone gradually changes from Bes to Es.
The first piano melody has a very jazzy after-beat rhythm, just Bes, Bes, Bes, Es, D. While the tonality is in Es, the Bes has a very important role in the melody. The contrast between the low tone of the voice in m. 12 with the piano interlude that is relatively high, gives some humor, just as the whole jazzy rhythm of the piano. In m. 17 the relatively large seventh interval in the voice gives an accent to "aus Ärger", while the downwards movements of the voice in m. 20-24 suggest the drive away.