Let them do what they want as long as they don't try to push their agenda on others. I personally don't believe in marriage. 2 hubbies is way more than any woman should ever have to endure!
These people just need to be honest about what they really want which is to be able to
Firetruck whoever they want without consequences.
Why marry anybody. Just firetruck who the heck you want and stop kidding yourselves about wanting any spouse.