Is a wife permitted to refuse her husband's invitation to bed due to her intense grief over the death of a beloved relative, without thereby incurring sin?

There is no doubt that a husband should be considerate of his wife's feelings, and thus should not approach her during times of sadness. However, if he requests her, she is obliged to respond, even if she dislikes it. This is due to the generality of the hadith narrated by Abu Hurairah: "If a man invites his wife to his bed and she refuses, and he spends the night angry with her, the angels curse her until morning."