I Knew a Woman- Roethke

I really enjoyed this poem. It was extremely uplifting and beautifully written. Roethke's observations of this woman's body are very graceful. To write about someone and say that they are beautiful in their bones is very loving. Roethke noticed everything about this woman that no one else did. The way she sighed in relation to the outside world, the way she moved, even down to compairing her voice to the voice of a goddess or a singing tone. I was interested in the very last line " These old bones live to learn her wanton ways." Now is Roethke speaking of himself or the woman. I can see both or maybe I am completely off. I'll explain; If Roethke is speaking of himself I imagine he is comparing every inch of himself down to his bones to this woman. If this is the case he wants to be everything she is in order to keep up or in other words be good enough for her. If he is speaking of the woman does he mean that eventually this beauty and grace that she embraces will fade? Or that eventually his love for her will wither? If he measures time by how a body sways is he speaking of youth?
I can understand that point as well...if he is speaking of youth I don't feel he is speaking about the outside perspective of a being. At one point in this poem he says " My eyes they dazzled at her flowing knees..." I don't believe he literally means he can see her knees but he can see how they let her move. He can see beneath her clothes, beneath her skin, beneath everything right down to the beauty of her bones. Everything only gets more beautiful from there.