Well, in my opinion, it's anticipation of divorce. Just my opinion. Would I sign one? Meaning if my potential wife had a lot of "stuff" and drew one up, would I? Probably not.
Actually, it's not just in anticipation of divorce...it can be for estate planning too. In the event a will is held to be invalid, everything is distributed to your heirs as determined by law. Different allocations are made for separate property than for community property...you can also do it to protect property...and I've heard it being done for tax planning purposes too... If you're 50 and you're marrying a 45 year old woman...and you both have kids from previous marriages...and you both have significant estates you wish to pass on to your kids...it's probably a good idea to set out from the beginning whose separate property is whose...that way there is no confusion when you die. Doesn't mean your spouse can't enjoy your stuff while you're married and alive. And of course, you can leave your spouse whatever you want in a will. One of the very first things I did as a lawyer was represent a side in one of these...I was kinda skeptical...I was called by a lady at my church who does estate planning...she was representing the wife and needed another attorney to represent the husband. It became quite clear to me that this was not at all planning for divorce, but rather planning for death.
