(a) As used in this article, the term "marriage articles" means any antenuptial agreement between the parties to a marriage contemplating a future settlement upon one spouse. Marriage articles, whether by parol or in writing, may be executed and enforced by a court of equity at the instance of the spouse at any time during the life of the other spouse, so long as the rights of third persons, purchasers, or creditors, in good faith and without notice, are not affected thereby.

(b) An agreement perfect in itself which needs no future conveyance to effect its purposes is an executed contract and does not come under the definition of marriage articles.