When you enter into a marriage, you do so with the understanding, at least in a general sense, that what's mine is now what's ours. In community property states, once you are married, anything purchased during the marriage and any money earned during the marriage belongs to the couple.
So marriage comes with the spirit of sharing. However, any inheritance, earnings or assets you have acquired prior to the marriage remain your own. In turn, any property acquired during a separation with the intention of terminating the marriage is separate property belonging to only the one who acquired it. However, in cases of separate property, you can merge assets or gift them to your partner making them community property.
If you or your spouse inherits or is exclusively given property or money during the marriage, that property is only considered the property of the designated recipient. Upon death, any community property becomes fully the property of the surviving spouse. Separate property will go through probate to determine how it will be distributed, should no will be in place. If the couple separates, the community property is divided equally between each partner.
Marital property laws are complex. If you need clarity in determining what is yours and what is not, a family law attorney should be able to look at your situation and your assets and help you understand how to maintain the status of individual property, or alternatively, to make them communal. When you have a lot at stake financially, there can be a great relief from gaining a full understanding of what assets may be divided upon divorce and what assets you or your spouse will keep.