Unmarried couples don't: Inherit each other's property automatically. Married couples have the state intestacy laws to support them if they do not have a will. Under the law, the surviving spouse will inherit (at the minimum) a fraction of the deceased spouse's property. Have the privilege to speak for one another in a medical crisis. In the case that your life partner loses capacity or consciousness, someone will have to make the go-ahead decision for a medical purpose. It should be you, but if you haven't filed certain paperwork, you may not have the ability to do so. Have the privilege to handle one another's finances in a crisis. A married couple that jointly own assets is less affected by this problem than an unmarried couple.