20 CFR § 404.332 - When wife's and husband's benefits begin and end.
(a) You are entitled to wife's or husband's benefits beginning with the first month covered by your application in which you meet all the other requirements for entitlement under § 404.330 or § 404.331. However, if you are entitled as a divorced spouse before the insured person becomes entitled, your benefits cannot begin before January 1985 based on an application filed no earlier than that month.
(b) Your entitlement to benefits ends with the month before the month in which one of the following events first occurs:
(1) You become entitled to an old-age or disability benefit based upon a primary insurance amount that is equal to or larger than the full wife's or husband's benefit.
(2) You are the wife or husband and are divorced from the insured person unless you meet the requirements for benefits as a divorced wife or divorced husband as described in § 404.331.
(3) You are the divorced wife or divorced husband and you marry someone, other than the insured who is entitled to old-age benefits, unless that other person is someone entitled to benefits as a wife, husband, widow, widower, father, mother, parent or disabled child. Your benefits will end if you remarry the insured who is not yet entitled to old-age benefits.
(4) If you are under age 62, there is no longer a child of the insured who is under age 16 or disabled and entitled to child's benefits on the insured's earnings record. (See paragraph (c) of this section if you were entitled to wife's or husband's benefits for August 1981 on the basis of having a child in care.) (If you no longer have in your care a child who is under age 16 or disabled and entitled to child's benefits on the insured's earnings record, your benefits may be subject to deductions as provided in § 404.421.)
(5) The insured person dies or is no longer entitled to old age or disability benefits. Exception: Your benefits will continue if the insured person was entitled to disability benefits based on a finding that drug addiction or alcoholism was a contributing factor material to the determination of his or her disability (as described in § 404.1535), the insured person's benefits ended after 36 months of benefits (see § 404.316(e)) or 12 consecutive months of suspension for noncompliance with treatment (see § 404.316(f)), and but for the operation of these provisions, the insured person would remain entitled to benefits based on disability.
(6) If your benefits are based upon a deemed valid marriage and you have not divorced the insured, you marry someone other than the insured.
(7) You die.
(8) You became entitled as the divorced wife or the divorced husband before the insured person became entitled, but he or she is no longer insured.
(c) If you were entitled to wife's or husband's benefits for August 1981 on the basis of having a child in care, your entitlement will continue until September 1983, until the child reaches 18 (unless disabled) or is otherwise no longer entitled to child's benefits, or until one of the events described in paragraph (b) (1), (2), (3), (5), (6) or (7) of this section occurs, whichever is earliest.