Is one sheep sufficient for us as an Udhiyah, or is it obligatory for each of us to offer a sheep?

If both spouses are financially independent, then each of them is obligated to offer an Udhiyah according to its conditions. However, if one of them provides for the other, then the Udhiyah is incumbent upon the provider and is waived for the one provided for. This is based on the Hadith of Abu Ayyub: "We used to offer a single sheep, which a man would sacrifice on behalf of himself and his household." The 'household' here refers to those whose maintenance is obligatory upon him or whom he voluntarily supports. It is permissible for a man to offer a sacrifice on behalf of himself and his household whose maintenance is obligatory upon him. He may also include in his sacrifice any of his children who have reached maturity, provided they are still under his financial care.