The marital portion provided under Article 2432 of the Louisiana Civil Code, whether in full property or usufruct only, or any portion thereof, may be placed in trust, if:
(1) The net income accruing to the surviving spouse therefrom is payable to the surviving spouse not less than once each year;
(2) The surviving spouse's interest is subject to no charges or condition, except that the trust instrument may place restrictions upon the alienation of the marital portion in trust; and
(3) The term of the trust, as it affects the marital portion, does not exceed the life of the surviving spouse.