Determination of marital status
For purposes of this section—
(A) In general Except as provided in subparagraph (B), marital status shall be determined under section 7703(a).
(B) Special rule for separated spouse An individual shall not be treated as married if such individual— (i) is married (as determined under section 7703(a)) and does not file a joint return for the taxable year, (ii) resides with a qualifying child of the individual for more than one-half of such taxable year, and (iii) (I) during the last 6 months of such taxable year, does not have the same principal place of abode as the individual’s spouse, or (II) has a decree, instrument, or agreement (other than a decree of divorce) described in section 121(d)(3)(C) with respect to the individual’s spouse and is not a member of the same household with the individual’s spouse by the end of the taxable year.