Yes. The default in state law, called “intestacy,” is designed with married couples in mind. If a married person dies without any estate plan, the survivor will get a good portion of the assets left behind. However, if you’ve not married, or you are in a state that does not recognize domestic partnership or civil union, your survivor would get nothing. Instead, the family of origin of the partner who died would get anything in that partner’s name, including bank accounts, real estate, etc.