It depends. A common law marriage – a marriage established when a couple presents themselves to the world as married but does not have a marriage license – is recognized in only a minority of states. If you live in a state that recognizes common law marriage, then you are considered married and should indicate that on your Marketplace application. You are still considered married even if you moved to a state that doesn’t recognize common law marriage after living in a state that did recognize your marriage. If your state does not recognize common law marriage, then you cannot indicate you are married on your Marketplace application. (IRS, Filing Status; Center on Budget and Policy Priorities, The Health Care Assister's Guide to Tax Rules, updated Sept. 2018).