A common law marriage is a legal marriage for all purposes under the law. If you meet the tests to be common law married in one state, then you are legally married forever, even if you later move to a state that does not have common law marriage (due to "reciprocity") and you can't split up without a real divorce with real lawyers, alimony, child support and a judge.
There's no asterisks, and no such thing as being common law married but also single. You are one or the other, period. And if you are married, you are married for all purposes (medical proxy, children, taxes, welfare, mortgages, credit card debt, and everything else.)
If you are not sure if you have a common law marriage with your partner, check the laws of your state or consult a family law attorney in your state. You may also need to determine the date the marriage is or was effective. (For example, most states require a public declaration. Even if you have been living together as spouses for many years, if you never publicly referred to yourselves as married in front of other people, then you might not be. You could fix that with a Facebook post, but then the effective date of the marriage would be the date of the post, and you would be single before then, possibly including on taxes. Again, check with an attorney if you are not sure.)
