Glad to hear this works for you. However, this kind of system seems intended for those just starting out and with very simple finances. It could also easily inspire resentment.

The reason I say “very simple finances” is that many people want to have income beyond just their job. People may also own assets, such as a house, that either provide income or shelter. How do you account for interest and dividend income, stock market gains (realized or unrealized), value of a house owned (which needs repairs and maintenance on an irregular basis), retirement or pension package contributions provided by one’s employer? Or just that one partner may have some savings and another does not?

And then of course there are expenses – the baby’s expenses being one obvious category that may or may not be shared by all partners. Also more mundane things, like one person spent more money than he/she could afford on a car, or another intentionally owns a very basic car, and the car(s) are shared by the household.

In short, I would find your system unworkable for all but the most simple households. But I do like that you bring up poly finances. In my mind, it works better when all partners who live together more or less have the same lifestyle. This often means one or more partners choosing to live well below their means, so as not to inspire jealousy or power issues with the others.

The partner who earns much less has issues as well. Such a partner would do well to save and develop their own nest egg. Kind of hard if others in the household are living a lifestyle way above one person’s means.

Finances can get quite complicated early on, even for a couple…heck even for a single. People’s values are reflected in how they earn/spend their money.