Well, R.J. H., what with the various posts about this type of situation in g2g and possibly the helping hand of someone who will help, Sir W.A. of Kittybrewster will resolve his dilemma.
He CAN of course "marry" them, contrary to the actual status and contrary to the laws of the land at that time. But then THAT would give a false impression also of their relationship or relations
He may indeed have to tolerate some "disjunct" family lines and plaster NOTES in various biographies and refer the reader to [[surname-xxxx|forename middle name surname]] on the profile of the woman and on the profile of the man, while at the same time somehow getting the message across that they were not legally espoused according to the laws of the land at that time ... which of course a certain percentage of readers will ignore
I don't doubt but what he is clever enough to find a work around for the situation; in fact I'm 99% certain there's some mentioned in the various previous posts on this type of situation