Maybe a bit late to comment - but it helps to put things in the social context of the time, where getting divorced was not only expensive but an ordeal and a huge social stigma - you basically had to go to court and accuse your spouse of horrendous cruelty or adultery - and name the third party. It stigmatised the kids, too.
19thC bigamy was more common than we tend to think, for those reasons, rather than plain deception. Quite often, not only did the second spouse know of the first, the first spouse knew about (or even knew) the second. Going through another wedding was sometimes the only way to embark on a normal post-(non)-divorce life without your younger kids being stigmatised as bastards (and possibly removed from their mother). Often the bigamist's siblings and parents were also in the know.
Maybe putting it in that sort of context if/when you explain it to the family (families?) might make it less shocking to them.