This reminds me of a neighborhood ghost from my childhood. Tragically watching but not part of the scene, but part of the emotion of those around and unaware.
But it also seems more real than that to me. It's the sadness of knowing that this one doesn't love as deeply as you. The window metaphor helps to create at distance and perspective. It's the stepping back of soul searching that creates a sad but melancholy mood. Its the knowing its got to change but not being ready for it.
I really liked this as an overall write. The flow and imagery work well.
I did like the imagery of the lady sitting at the window. Like a lady in her most natural state, in love. Still the insecurity or doubt that flows in and out of this piece paints a true portrait of the reality of that love.
(they're rotting from neglect)
I think this best describes the root of the problem you have introduced here. Neglect, she still feels that she has failed somehow, fixed on her part in their decay, the guilt that sits in this statement sets up what you are trying to say, makes the connection between her and the man she loves.
It is her most natural desire yet
And deceitfully vows for not long
How sad! Even though he fancies her, he is "enchanted by his temptress" she still feels by the introduction of the neglected fingernails that there is something not good enough about the situation that she feels responsible for.
I like this piece.
I think it resonates with the truth that most women face through out their lives.
Yet I believe should we ever really appreciate our role as woman, this would go away and the pressure that we put on ourselves to be enough would fade where we could freely love with abandon.