There is no way on earth your H should take the "deal" of money for a child. No amount of money is worth it, for one thing. Secondly, it is an old trick. They get you to make the agreement, then they flaunt the agreement to the kids and to the judge, as proof that all you really are doing is extorting money, not caring about your kids. She doesn't have to give you a penny to win it all at that point.
Bear in mind that what she is suggesting is probably not even legal. The money is for the kids, not either parent. She should have been spending it on the kids, not saving it up.
What she is suggesting is a lose-lose deal for the kids. They lose their father AND they lose the financial support they deserve.