CALIFORNIA FAMILY LAW
...Premarital and Postnuptial Agreements
......Agreements Not Enforced
.........Burden of Proof re Validity
3 Cards On This Topic:

Party seeking to enforce premarital agreement has burden of proving that it was entered into voluntarily. (Fam. Code §1615.)

Party challenging agreement has burden of establishing that it was involuntary.

Burden of proof re validity of premarital agreement falls on party challenging agreement.