A speaker sits with a woman who is crying hard, and all he can see is how beautiful she is. The line "She's so beautiful" comes back again and again, like a refrain he can't stop repeating. It works almost like a heartbeat running under the poem, and it shows how completely his attention is fixed on her, even at her most upset: red eyes, shaking shoulders and all.
His feelings shift as the poem goes on. He begins with simple tenderness and promises to hold her "to the end of forever," then adds a quieter, more honest condition: "or until she doesn't want me anymore." Later, anger and helplessness creep in. He asks who could hurt her, and admits he can't take her pain away. All he can do is hold her and love her.
The mood is gentle, sad and devoted. It's less a grand love poem than a small, intimate moment of comfort, where being present is the only thing he has to offer.