Nicodemus was tired of seeing her raise her wand to him. Who did she think she was? But he had no way to really parry the spell, and was hit squarely. He froze in his spot, unable to move. Why did she keep doing this to him? What had he actually done to her? He only wanted her soul - well, and body. He wanted to tell her that he was going to have her and he didn't want her husband. Her husband was just being used as a vessel for himself, not as something important.