I have a few of these situations in my line. I have one woman I tracked for over ten years ( obsession ). I found she had been legally married a minimum of five times, once in a name made up of various family info. However, though I have tracked religiously there is only one possible divorce thus the chaotic records. She would also list herself as a widow though all husbands were alive.
My great grandfather left a wife and six children and took up with a younger woman, my great grandmother. Until the time of her death, the first wife listed herself as his wife and eventually widow. My poor grandfather lived with this "scandal" as if it were the worst thing in the world.
I honestly think with poor record checking, people just became whatever was easiest to accomplish their goals. I.e. lying to marry when they were underage or already married.
But they do make life fun, you should have heard me when I finally puzzled out a possible place of death, different possible names, and "viola" I found her death certificate and burial after ten long years.