Having sex with the daughter is sexy and hot but marrying the daughter is kind of weird.
Yeah, Incest is common it would seem, and a BBC TV report a while back estimated around 70% of the UK population had experienced an Incest relationship somewhere in the Family at some level, and i found that unbelievable and very shocking for the so called modern 21st Century. I cant find a link to the item as it was aired on TV, maybe a news broadcast, but not important now, maybe if i find it i will post here, but this might interest you:
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However, having consensual incestuous sex is one thing, marrying a relation back to Grandparents is a no no in most places as far as i know, officially. But guess if a couple really wanted to marry, then ways could be found where they can. I know of several first cousins who had incestuous relationships, and then married later with what seemed the blessing of the Family, and had the marriage registered legally in England, in the 19th Century. (i study Genealogy). That was first cousins, and not of course Father Daughter as in DmD, but if false documents were made at a high cost i would imagine, like two Birth Certificates by some shady crook, and MC never mentions about his marriage to Rachel, and the divorce at registration, and no tricky questions about similar surnames if they are altered on the Certificates. Either way, would D be happy getting married with false details, and not under their own names perhaps?
Of course in the 21st Century, it is far more easier to check details online at the Record office for many Countries, and many Genealogy websites, and the Registrar might possibly do that if he/she expected something was not right. Then the happy couple could be looking at a few years in prison, separated, with MC told to not see or visit D ever again, except perhaps when her mother Rachel was present. I am not sure if a certificate check is mandatory now anyway, and if that is the case then there is no hope for the happy couple ever getting hitched, imo. But i could be wrong.