Fair doesn’t mean “equal.”
The most equal trade in the world is this: I give you a dollar and in exchange, you give me a dollar. Perfectly equal, and equally pointless.
Lots of trades aren’t equal, but they’re better than fair – they’re win/win. I give you a dollar and you give me something that’s worth more than a dollar to me, but less than a dollar to you. Since “worth” is entirely subjective, this helps us both!
So what is a partnership? It’s not a permanent, equal exchange. I mean, it can be that, but that’s not super great. If two people can each afford $2k in rent each month, then splitting the rent on a $4k/month place might get them marginally better living conditions than two separate $2k/month places. Or maybe not – do you value more space or more privacy?
Here’s a better option – two people that can’t afford equal amounts of rent living together and finding ways to create win/win trades. Maybe the person who makes more money has no time to clean. Maybe the person with less money has more time to paint. And so on.
Look at business partnerships. When you see two people partner up to start a business, it’s not because they have identical skills and are splitting the work into two exactly even piles. It’s because they have complementary skills, and the division of labor creates a mutual benefit.
So don’t look for trades, partnerships, and situations where you get out exactly what you put in. You’ll be miserable. Look for situations where you get out exactly what you want – and you put in whatever it takes to get there.