without any deeper analysis, i would immediately say this is likely written about sharing affection with an unreciprocating lover, but with virtue of my lyrical preferences, i like to make connections that mean whatever i want them to mean. i think that is the beauty of lyricism, it's never meant to really mean one thing. i have a gripe with artists who prioritize single-meaning compoundings of words.
But I'm a giver and he's immune
He is hungry for someone but doesn't know who
I'm a giver, he's the moon
And I reach and I reach and I forgive the girl who let you
this part, it means the most to me. "his" immunity and hunger contradict one another, representing our writer's ill fated relationship. the result of a man who paradoxically wants to receive said affection, just without the correct target at hand, sends our giver into spiral, extending herself only so, so far. devil's advocate would say is it really his fault? maybe he is just a man, yearning, seeking comfort in the accessible avenue of the unlucky giver. "i forgive the girl who let you." now that's a bittersweet ending, closing off with the sweetness of self-forgiveness. something i think we all struggle with. a lot.