Somewhere in his relationship, diseases intertwined and by doctor's orders, said person couldn't be in a relationship with significant other. And he believes he wasn't good enough, but still wants her to succeed. She starts hating him.Wanting him dead. Somewhere after this, she dies. He starts recollecting on memories of her, but she'd rather have him dead than honestly speak of her attempted murder against him. This theory is all over the place, but it's all I could come up with.