I think Dressed2Depress had it right, in that the narrator resented Joy's depression, since it robbed him of his own happiness. The narrator hints that Joy was guilty in some way when he asks if it was "an act of contrition" that caused her sorrow, suggesting that she deserved it (in his own mind). Also, he makes sure to point out that the daughters were "their mother's children," which could only add to his sense of loss and feelings of resentment.
I think Dressed2Depress had it right, in that the narrator resented Joy's depression, since it robbed him of his own happiness. The narrator hints that Joy was guilty in some way when he asks if it was "an act of contrition" that caused her sorrow, suggesting that she deserved it (in his own mind). Also, he makes sure to point out that the daughters were "their mother's children," which could only add to his sense of loss and feelings of resentment.