Why does the husband not participate in paying the aggravated blood money for involuntary manslaughter?

The aggravated blood money is to be paid by the 'Aqilah collectively, who are the male agnates (relatives on the father's side), based on the Prophet's (peace and blessings be upon him) saying: "He ruled that the blood money is to be paid by the 'Aqilah." If the husband is among the 'Aqilah, he is obligated to pay with them; otherwise, he is not.