I have a couple theories:
The more he tried to satisfy her by changing himself/the world, the less important he became to her, and thus he fades out of her life.
He's dead, and she's reliving the memories of their relationship through his gifts.
The game design is okay. It was paced very slowly, and the rewards weren't satisfying enough. It felt kind of bare bones, but that fits with the premise of the game I suppose. It did a good job of making me think however.