Commanding Officers could not really stop soldiers getting married while they were at Home. There weren't many barracks at this time so most soldiers were billoted on the population. So again the CO could not really stop soldiers and their wives cohabiting. The crunch came when the regiment was ordered overseas.
Before the marriage roll became official it is thought that, as far as Private soldiers were considered, they would have been a ballot as to which wives (and children) could go with the regiment. The rest would have been left behind, and because the pay of a Private did not allow him to save much money, it is likely that the wife and children had to return to her home parish. As I am sure that the parish of the seaport they sailed from would not want to keep them on their parish relief.
This is really non-military. You may get a better answer on a general section from someone with knowledge of the treatment of the poor.
Ken