The issue is predicated upon a provision of the Internal Revenue Code which allows, as a marital deduction, a gift tax exemption of transfers of certain life estates to donee spouses. For the exemption to apply, the donor must create a Qualified Terminable Interest Property (QTIP) trust. . . . In general terms, transfers between spouses qualify for a marital deduction and thus are exempt from gift or estate tax. 26 U.S.C. §§ 2523(a), 2056(a). However, if the transfer is in the form of a life estate or other terminable interest, the marital deduction is generally not allowed. 26 U.S.C. §§ 2523(b), 2056(b). These provisions notwithstanding, a further exception is allowed under the gift tax for qualified terminable interest property. 26 U.S.C. § 2523(f)(1). That interest is defined in § 2523(f)(1) as one “in which the donee spouse has a qualifying income interest for life . . .