The answer is very rarely, as long as it is properly drafted and entered into by the parties. New York courts have consistently enforced prenups that are not tainted by fraud, undue influence, duress, or other bad conduct.
Below are some recent New York prenuptial agreement cases where the courts have looked at the validity of specific prenups.
Gottlieb v. Gottlieb, 25 N.Y.S. 3d 90, 138 A.D.3d 30 (2016):
Court upheld a prenuptial agreement as valid and enforceable even though one party was keeping much more assets than the other party. The Court declined to undo the agreement because one party now regretted the choice to not ask for more in the parties prenuptial agreement.
Gutherz v. Gutherz, 992 N.Y.S.2d 158 (2014):
Court found that the party trying to throw out the prenup failed meet the burden of proof to invalidate a prenuptial agreement. Court found that “an alleged failure to disclose assets does not, standing alone, constitute fraud or overreaching sufficient to vitiate an agreement, particularly in the absence of evidence of an attempt to conceal or misrepresent the nature or extent of the assets.”
A.N. v. E.N., 960 N.Y.S.2d 48 (2012):
Court set aside a prenuptial agreement on the grounds of it being unconscionable, overreaching and duress during the execution of the agreement where one spouse had no input in negotiating the terms and the agreement was entirely one-sided. In this case, the terms of the agreement the one spouse actually signed were very different from the actual terms of the agreement.
E.C.-P. v. P.P., 946 N.Y.S.2d 66 (2011):
Court threw out the prenuptial agreement where the signing of the prenup was fraudulently induced with promises that the party asking for the prenup would tear up the agreement after they had a child, but then failed to follow thru on that promise. The case demonstrates the importance of a properly drafted and executed prenuptial agreement.