You were cruel, selfish, and controlling. Yet even if he knew how unhealthily this relationship was, he stayed. He chose to be with you until the very end.

It's simply because he still loves you, a bit too much.

The word obsessed best describes him. He's obsessed with you—to the point he'd allow you to neglect him, degrade him, even abuse him.

It's toxic, and he's aware. It doesn't matter to him. He'd allow you to do anything you wish to do to him and his body—he doesn't resist.