20 CFR § 219.50
When evidence of “living with” is required
February 18, 2021
Evidence of “living with” (see part 222 of this chapter on Family Relationships) is required when—
(a) The employee's spouse applies for a spouse's annuity as a deemed spouse; or
(b) The employee's legal widow or widower applies for a lump-sum death payment, annuity payments due the employee but unpaid at death, or a residual lump-sum death payment on the basis of that relationship, or the employee's deemed widow or widower applies for a widow's or widower's annuity.