I-864 is for the sponsor while I-864A is for a sponsor’s household members whose income was jointly filed in tax and will be used in the petition.

Nop, if you are the petitioner or sponsor just file a I-864.

@vico if he is using income from another household member too, e.g joint filed tax with wife. his wife would file I-864 A along with his I-864

yes. that's correct.

But I'm not using my wife's income, since in my tax return I am single.