I notice that one marriage was before the Great War and the second one after. If your relative was not English, an enemy alien, his English wife would have benefitted by divorcing him. I have a relative whose case was similar, though I'm not sure whether his second marriage was a synagogue one, but it took place abroad.
A second thought is that divorces were expensive as well as frowned upon, so lying about the split may have been mutually agreed..
