You might be thinking of inheriting the spouse's half after death.
Internal Revenue Code section 1041 provides that a transfer between spouses, or former spouses, “incident to divorce” is not taxable in most circumstances. The transfer is treated like a gift. The transferee takes the transferor’s tax basis in the property. The effect of the rule is to defer the tax consequences (recognition of gain or loss) until the transferee disposes of the property.
