I did wonder about the scars...
On the one hand I don't think his complaints about her reluctance to have children would be necessary for a "prison" plot. On the other hand there was a huge amount of unnecessary stuff in the Paul story that led precisely nowhere.
Didn't Rob say he left a job he loved (in Canada) so she could look after her aged parent? She could have been in prison there - but surely she wouldn't have had time to get banged up since they arrived in England? It's entirely possible that aged parent may be looking after her....
I still think she may never actually appear - Rob will forever use her as an excuse to keep Helen in her OW place.