I-864 help

[SKSP]

My husband is filing I-485. Because I don't meet the income requirement, we have found a Joint sponsor who is willing to fill up I-864 for him. The would be joint sponsor is a married man with two children. He has filed Marriage Filing Joint in the previous years's tax return. His wife had income in the past two years, but currently she does not work. In this case, would she have to filed I-864 A for me, or just the I-864 from the joint sponsor is enough ?

Thanks in advance.