What about this couple?
1871 census
1 Collingwood Place, Portsea
John Barnes head m 38 labourer general b Wareham
Elizabeth Barnes wife m 36 b Langton, Dorset
1871 census
I thought perhaps if she had run off with a relation of her previous husband, and so didn't change her name, she might not have seen the need for another marriage ceremony.
More likely than not she probably just needs to be eliminated though, but I'm having trouble with that!