Spouse retains full rights to estate, unless there is a divorce.
There were two deaths in the celebrity world recently that involved separations, highlighting a peculiar issue in estate law, according to Forbes in "Kate Spade, Anthony Bourdain And Estate Planning When You Are Separated."
The deaths were of fashion designer Kate Spade and celebrity chef Anthony Bourdain, who committed suicide while being separated from their spouses. If Spade and Bourdain had gotten divorces, then their spouses would not be entitled to any portion of their estates. If the spouses were included in the estate plan, they would be constructively written out by a court. However, that does not happen when a couple is separated.
The spouse of the deceased retains full rights to the estate. That means if there is no estate plan, the spouse will normally receive the entire estate through the laws of intestate succession. If there is an estate plan, then the spouse receives anything the plan says he or she gets. If the spouse does not receive enough of the total assets of the estate, then the spouse can elect to take his or her spousal elective share (the amount varies between states).
Reference: Forbes (June 12, 2018) "Kate Spade, Anthony Bourdain And Estate Planning When You Are Separated."