As an early poster said, probably bigamy was far more frequent in late 19th / early 20th Century than we usually think - people were disrupted by Wars, and more movement of labour, and it seems to have been very difficult and expensive to get a legal divorce, so I can really see why many probably thought "Hang it .... I'll move to X, and start all over again" then "Well, no-one here will know I'm married..." then "Bachelor... yes, that's right" and just start all over again.
Or simply - we, researching, cannot find a marriage simply because there is no formal marriage to find, and we try for years to track one down.
Many war-time marriages seem to fail, often because couples married before they'd really had a chance to get to know each other. We'll probably never know the true statistics on this, because it was only the ones who got caught out that we know of.
And "lower class" people probably wouldn't have known how to even set about getting a divorce, even if they'd been free!
Families even when I was young often felt there was a disgrace in having had a divorce in the family, even where the family member was not in any way at fault. It was almost as if they felt it might contaminate them all! Whispered conversations, all the way.
- It's quite fascinating, isn't it?