I'm loving the Replacement 
I think Ellen's husband also treated Paula. The years she alleges she spent child rearing were probably spent as a psychiatric patient. Probably connected to post partum psychosis/loss/separation.
I don't think Paula has a child or not one in her custody anyway. I think the 10 year old is probably a step child or neice.
Georgia has me a bit stumped. Could also be a past psychiatric patient, ex work colleague, ex of Ellen's or Kay's husband.
Kay's husband is definitely dodgy as is Ellen's husband. Kay stumbled onto something amis and that's why she ended up dead.
Roll on next weeks episode!!