Only a certain number of soldiers were granted permission to marry, this was known as marrying 'on the strength'. This allowed the couple to live in married quarters and the wife and children had rights to various payments or allowances. If a soldier married without permission, the wife and any children could not live together and had no rights to any allowances, pension payments etc. I can't remember if this is all correct from memory but you get the idea.
I wonder if this second marriage was conducted after permission to marry on the strength was given?
