Yours, Mine, and Ours - Who Owns This?
When marriages are running along smoothly, income and assets are usually shared generously, regardless of who owns them on paper.
In most states, the two of you have a good deal of say over who owns them on paper. Only nine states in the US are community property states, where both partners share equally in each others' incomes and new assets. (The nine are AZ, CA, ID, LA, NV, NM, TX, WA, and WI. AK and PR allow but do not require sharing.)
Good stuff to know when you're deciding whether to marry someone or when you're divorcing or protecting yourself from the effects of a spouse's addiction. Quite unhelpful otherwise.
Why? Because owning something or half of something creates expectations, and an expectation, especially in marriage, is a premeditated resentment. If you don't have enough of something to share generously with each other, doing what you can to bring in more of it will gain you a lot more love than taking it from your spouse will.
Expect Love. If fairness is what you want, find a business partner, because expecting it really gets in the way of receiving the precious commodity of love.