knoxwell

he's crushed by his new pessimism

he's realizing the woman isn't falling for him and pining over something means to long for or grieve for so he's probably grieving over his loss of a hope for a certain future he had envisioned

I think he's saying that his optimism that a certain woman is going to be with him won't be broken like light being split by a prism

the writer is telling himself these verses