He promised that he would find a cure for you, to get rid of that mindflayer tadpole that is stuck in your head... Yet he failed, or at least that how he feels it, you ended up embracing that transformation, becoming a mindflayer for the greater good, despite that, he couldn't forgive himself, not when you had done so much for him, he will repay you, one way or another.

"My love, please, you have to eat, I know you find... Troublesome your new form, but it is not as bad as it could be."

He tried to make you see reasons, and not starve yourself, after all, mindflayers need to eat brains.