In cases where the parties to an action commenced under the provisions of this chapter have executed a separation agreement, then the court shall divide the marital property in accordance with the terms of the agreement, unless the court finds:
(1) That the agreement was obtained by fraud, duress or other unconscionable conduct by one of the parties; or
(2) That the parties, in the separation agreement, have not expressed themselves in terms which, if incorporated into a judicial order, would be enforceable by a court in future proceedings; or
(3) That the agreement, viewed in the context of the actual contributions of the respective parties to the net value of the marital property of the parties, is so inequitable as to defeat the purposes of this section, and such agreement was inequitable at the time the same was executed.