In regards to my case, my joint sponsor filed taxes jointly with his spouse but she didn’t earn income. So I didn’t add her to the I-864 or submit an I-864A as many people suggested I do. However I did have his spouse fill out an I-864A and took it with me to the interview in case they asked for it. They did not so I did not give it to them and we got approved no problem. This happens to a lot of people.