For goodness sake, so many contortions tomtry and explain a verse whose meaning I would have thought was obvious if you realise just one thing.

The song comes from a time when even for the wealthy, divorce was all but unobtainable and if you weren't wealthy chances of divorce were zero.

So once she was married that's it, there's no going back and his chances of persuading her to come back to him are zero - that's if she ever wanted him in the first place and his affection was always one sided. Either way the verse is simply a statement that she's not attainable any more so stop whingeing and get on with your life.