In the process of trying to preserve her beauty in his paintings, he tore her apart, broke her, and made out of her, an ugly monster. The sight was now ingrained into his brain, her wide eyes as she screamed at him, accusing him of loving a fake version of her, of loving a painting, more than he loved the real her. While she slowly killed herself, he drowned in madness. The madness took over at some point. His paintings were now covered in sin. In bold. In the end, he burnt everything. His paintings, his house, and himself. A cleansing on sorts.
And that was that. The end of a painter and his muse.