In the USA a number of states are de jure community property states. In those states, assets acquired in marriage, and appreciation in value of assets owned before marriage are both considered to belong equally to both spouses.
Many other states are de facto community property states. There is often some sort of "equitable" division of assets in a divorce. In practical terms this often appears quite similar to the de jure states.
One of my favorite quips was from Tom Arnold, during his second divorce. He said something like "she wants half of half of Roseanne's money".
