I have seen and worked with a lot of prenups. They’re not always valid, particularly when they’re unconscionable or extremely one-sided. In my state, you can’t write a valid prenup that essentially cuts one party out without some countervailing, and reasonably equivalent consideration.
Nor should it be valid. If you are a physician and (let’s say) your intended’s best vocational prospects are unskilled labor, it’s simply unconscionable to exact an agreement in which, if there is a divorce, she goes to the factory floor and you enjoy a six figure salary and all the assets that salary has gained over the years of the marriage. This is the woman who will be bearing and largely raising your children. Divorces can happen for all sorts of reasons, and for you to assume that only the misconduct of your spouse could possibly cause one is presumptious in the extreme. How can she be sure that your position of absolute economic superiority will not lead to an intolerable vanity on your part? And how are you going to write it? “She gets nothing unless I commit adultery”?? One spouse being a physician (or a lawyer, or a high-level exec) is really hard on a marriage because the profession is so demanding.
At some point, one simply has to accept it that life has certain perils, and marriage brings many. The answer is not economic imperialism. If one cannot accept the risks of marriage, one ought not to marry.
It has been my practice, anyway, to discourage prenups except when the purpose is to ensure the division of already-obtained assets and their increase among the children in a “mixed” family; the real purpose being to avoided future conflict among children and/or surviving spouses.
I have seen lots of physician divorces, and they always hate what happens. But physicians can earn their way out of it, and should.
And, by the way, distributing trust principal to an 18-year-old is very unwise. Never have I seen an 18 year old fail to squander it. Better think in terms of age 25, at least.
I am unaware of any Church rule that says you can’t have a prenup. But I will say that some I have seen are, in my opinion, profoundly immoral on the part of the dominant party. But fortunately, the Courts often won’t enforce the most unconscionable ones.