A song plays, and the speaker is thrown straight back to a former lover. They wonder whether they still cross that person's mind, then answer their own question: probably not. From there the poem turns into a kind of self-sentencing. The speaker admits to breaking the other person's heart and decides that the only thing they deserve is hatred, even a terrible curse.
The repeated line "If I deserve anything" works like a judge reading out a verdict, and each time the punishment gets harsher. The third time, the speaker says they deserve "anything but having you back." That's where the guilt is clearest.
Then the final line cracks it open. After all that logic, the speaker still wants this person "so damn badly." The mood is raw and regretful, and the plain, blunt language makes it feel honest. Knowing you're in the wrong doesn't stop the longing.