Is the Udh-hiyah (sacrificial animal) due on both the husband and wife if both of them get earnings?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Offering an Udh-hiyah is an act of the Sunnah and not an obligatory duty, according to the majority of the scholars. It is an act of the Sunnah for a free person who can afford for it regardless of whether he be a man or a woman. It is valid, in the Sharee'ah, for the husband to make his wife share the reward of the Udh-hiyah with him because the Companions did so during the time of the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, according to the words of Abu Ayyoob Al-Ansari as he said, “A man used to sacrifice a sheep on behalf of him and his family.” [At-Tirmithi; Al-Albani: authentic]

However, if each of them (husband and wife) offers an Udh-hiyah on his own, then there is nothing wrong with that.

Allaah Knows best.