system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: A prenuptial agreement, in regards to division of property, is a perfect valid agreement, and shouldn't have a negative stigma.

I find that this can be seen upon as greed or egotism, hower I simply see it from an economical standpoint.

When you're in a relationship, and you split up, you normally divide things by who it belongs to, even if there is a major difference or similarity in income. I bought the TV, I should keep the TV. You bought the couch, you should keep the couch.

This suddenly change when you enter marriage. The division is now 50/50, even though the contribution could be 90/10.

I come from en economic background, so I just see it as asset placement. The one who contributed the most, should have the most in a settlement.

I know there is such a thing as an enabler. If one partner allows the other partner to work more or be more effective, this can contribute to the overall utility of the home. I.e. the example of the 60's family where there is a houseworking woman and a working man. The woman does all the work at home, so the man can focuses on his work, bringing home income. However this model can't be accurately projected into the present world, where both men and women work equally and split house chores.

So I would find it completely valid if a woman, on average over the period of the marriage, contributed double what her husband did, she should receive double the amount of assets as him. The same goes the other way around.

Take an example of a firm on a stock market. There are 100 contributors to the firm (100 shareholders), 90 of these hold a total value of 9% of the firm i.e. 0.1% each. The remaining 10 hold a total value of 91% of the firm i.e. 9.1% each. If the firm closes down, the assets of the firm shouldn't be split in 100 equal parts. No, it should be split by contribution to the firm. The same goes if the firm produces a dividend, the dividend should be split according to contribution and not equally. This is also how firms legally work.

By splitting it equally it removes the incentive to invest more, why should I invest more than the bare minimum if I'm only able to receive the average under all circumstances?

Now take this back into the relationship, if my spouse produces x amount of income and "invest" it into our shared life (Contribution), why should I invest 2x or 100x? I know it's an extreme example, but it gets the point across. Only if I know that I can keep the difference, I have an incentive to invest. Everything else is irrational.

Please take in mind that I'm not up for the "You bought this, you keep this" mentality in a marriage, since you could have split your income in-equally i.e. I buy groceries for the month, and you buy the table and chairs we need. If one only buys all the necessary items like food and general supplies, this should be seen just as much of a contribution as buying a table and chairs, under the assumptions that these equal in cost. I'm only focusing on contribution.

As I said, I've not taken any sociologic or politologic assumptions into my thoughts, only the economical aspect.

Hope you can help me out here. I've presented my views to friends and family over the years and most of them sees this as greed or like I have egotistic views. I simply can't see why I should contribute with twice as much as my spouse and expect to share equally. Or how I cannot feel guilty by contributing half as much as my spouse and expect to receive equally. 

This is clearly hypothetical.
gpt
Problem is that a lot of contributions are difficult to assess. 

House chores has to be done. How much should this be taken in account in the "full economical" point of view ? Hours at minimal wages ? Hours at your current wages in your work ? 

What if you got children ? You both wan them, but it's obviously the wife that is going to be pregnant, have to take some maternity leave etc. Maybe she'll miss a raise because of that, can you account it in contribution model ? 

Basically, the 50/50 split is saying "we both contribute to our family in different ways, and as quantifying it is really too complicated, we consider we do half each". 

*TL;DR*
If both of you are persuaded that one partner is going to contribute way more than the other, then a prenuptial agreement will be necessary. But people tend to consider than a relationship where there is a main contributor and a "freeloader" is not a healthy relationship, thus are retro-propagating this impression onto the agreement, which looks like "ok, we are marrying knowing that we are in a dysfunctional relationship", and it looks weird.