> Power imbalance is the consequence of marrying up/down economically.

It shouldn't be in the long run. You might go in fairly imbalanced but that imbalance should shrink over time.

Just like one co-founder might bring more capital into a business, but they both work at it and become more equal over time.

If not, that's not really a partnership-- it's employment.

> Seriously, say I am building a company worth 100m on paper. You think if I marry someone she should be entitled to a large fraction of that? Why? Let’s assume she doesn’t do anything with the business.

Building, not already have built. If you are the sort of person who could build a $100m business and your prospective partner isn't someone who amplifies your potential substantially then you are selling yourself short.

I think many people underestimate how enabling a good spouse can be to their business success when the spouse isn't directly helping in the business. Even if they do nothing more than consistently provide emotional support and stability, provide you with intimacy without the drama potential of dating, and offer you an occasional outside perspective that you can trust to not turn on you-- then that alone is a tremendous value that would be difficult to buy at almost any price (or at least at any price you could afford _before_ you built the $100m business). And that alone is a pretty low bar.

Often one spouse or the other takes a major career setback in order to manage the household and children, in many relationships your spouse is a trusted advisor that helps you navigate the politics of your industry or by giving you the confidence to make extremely risky moves by letting you know that even if everything goes wrong they'll still be there with you. A great partner enhances your success by adding additional meaning to your life and reasons to be successful in the first place, they coach you, and pick you up and dust you off when you're down.

If you're actually capable of building a $100m business you deserve a spouse of a similar caliber-- with at least complementary skills. And if they're actually enabling you, then -- sure they do deserve a decent chunk, perhaps not half, and perhaps it would be reasonable that they shouldn't be able to force you to liquidate your position.

And since you haven't built that $100m business yet there is a extremely high risk that you won't succeed in at all. The vast majority of businesses fail. Your spouse takes part of that risk too, so they should also get part of the payoff.

Someone who loses the financial standing that you built as a couple isn't someone who had their class elevated by your relationship-- they're someone who just temporarily had the ability to make use of the benefits of your class by proxy.

As you said,

> gets access to some of that

That sort of thing easily becomes toxic-- resulting in people staying with people they can't stand because they'll be financially screwed if they separate.

Going back to the business analogy... you and a partner create a business together and you manage to get them to accept an agreement that gives them only a tiny portion of the equity you received because you provided some initial business contacts or capital or whatever excuse. But after that, you both worth hard at it. When down the road your position is worth $10m and theirs is worth $200k, whats that going to do their loyalty and dedication to the effort?

When that business started perhaps on day 1 it was worth only the (say) $200k you put into it. Over time it grew to $10.2M in value, and both of you worked for that increase. So in the beginning your split should be 200/0 and towards the end closer to 5.2/5 or at least that's an outcome that won't produce loyalty and motivation problems.

> Flip this around. Suppose I’m a lowly programmer. I marry a super rich supermodel. Am I entitled to her money just because?

Her money from her 'super rich' status before your marriage? No-- and a no-prenup marriage wouldn't entitle you to it. Assets you owned coming into the marriage don't get split. A share of the assets she earned while you were married? sure! Presumably you were contributing substantially, even if not by bringing in piles of income yourself, or otherwise why the heck would she have married you?