What's a summary example of what your prenup would say?
I could see why one might be necessary. A 'divorce' could happen on a legal level, for moral reasons, and the marriage not be affected. For example, say a husband needs to 'divorce' his wife because she's addicted to meth and he needs to separate her from the children. In this case, a 'divorce' would mean to protect his credit score, his bank account (so she can't steal $ for drugs), and his other property - so he can raise the children.
I can see a prenup being needed if your wife accuses you of 'cheating' or some other b.s. and then tries to get your stuff. In that case, my opinion is that a prenup would say "in the case of a civil divorce, all assets are split 50/50, in accordance with moral law, and if you decide to separate from me, no alimony is required in the future."
Morally, a father would be required to support his children, but I wouldn't want a court getting involved in 'child support' payments. Really, this whole topic is crazy to think about. So many unknowns.
...But if you didn't get a marriage license, then why is a prenup even needed?
And to reiterate, the man should never get a State marriage license, lest he lose his sovereignty as a man and set himself up as a target for legalized grand larceny by the woman in a State where common law marriages don't exist, and he doesn't get a prenuptial agreement.
The avoiding of a marriage license is an interesting topic, from a legal perspective. Not having one would affect many things (but there could still be a legal fix, you'd just have to put forth more effort to fix it). For example, you would lose the "spouse is automatically legally recognized as your spouse" in:
1. Tax return. I'm not sure you could file 'married, joint' anymore.
2. Will. You'd have to hire an attorney to write up a good will to recognize your non-legal spouse.
3. Insurance, of all kinds.
4. Hospitals, life-or-death situation. You'd have to make sure your non-legal spouse could be present/make decisions if you were in a coma, or even to visit you (in certain circuмstances)
5. ...I'm sure there's more. Whatever situations that "gαy couples" had to face before the supreme court "ok'ed" their "unions" would apply.