These words are followed by a period of silence that cannot be filled by any degree of pain, rage, frustration, confusion, or other emotions born of his exasperated mind.
The silence is, therefore, undefined.
He sits next to her. He wants to ask her what it is, exactly, that she is under obligation to do and who, exactly, has placed her under obligation.
He does not ask this, however.
Nor does she say anything further in explanation.
There is nothing to say.
Because it is impossible for him, and perhaps even for her, to choose something that is proper to say.
He says nothing because he cannot bring himself to say anything because anything that he says will lead her to answer him, and any answer she gives him will checkmate him.
That is the word that comes to his mind. Checkmate.
She has blamed him, in a long ago past, for looking at all social interactions as competitions. As having winners and losers.
He has accused her of saying this to him as a means to check any further reactions on his part.
Much as when one tells you not to be defensive.
There is no response to this.