For purposes of this subchapter, the term “eligible spouse” means an aged, blind, or disabled individual who is the husband or wife of another aged, blind, or disabled individual, and who, in a month, is living with such aged, blind, or disabled individual on the first day of the month or, in any case in which either spouse files an application for benefits, on the first day of the month following the date the application is filed, or, in any case in which either spouse requests restoration of eligibility under this subchapter during the month, at the time the request is filed. If two aged, blind, or disabled individuals are husband and wife as described in the preceding sentence, only one of them may be an “eligible individual” within the meaning of section 1382(a) of this title .