Some states recognize common law marriage, basically if I understand it correctly, if a couple present themselves and act as if they are married for a pre-set time, they are legally recognized as married.
If I got that right, how does that apply to same sex marriage, in particular if the couple was in a obviously marital relationship for the required time but the law that allowed SSM was past after they started that type of relationship. Would the common law marriage ‘time limit start date’ apply to the date they started living as married (and before they could be legally married), or the date that allowed SSM, or does common law SSM not exist at all?
Iowa, Rhode Island and DC now recognize same-sex common law marriages on the same basis as opposite sex marriages. The courts of the other states where CL marriages are still recognized have yet to weigh in (and most of them only recognize CL marriages that occurred prior to some date in the 1990s anyway.)
To constitute a cl marriage (in about a dozen states that still recognize it), no preset time is needed. The couple have to live together, intend to be considered married, and hold themselves out to the public as being married. Of course if they lived together for only a short time, their intention to be considered married would be questionable. Thus your question is moot.