I was reading through the books, I haven't finished them yet, and I realized something.
Even after adopting the Faith of the Seven the Targaryens continued to practice polygamy, up until the dragons died out and they no longer had the power to enforce it.
What if there was a "Heresy" of the FotS, that only appears via event if you hold the Iron Throne or Kingdom of Westeros and if you have a Dragon, that allows for Polygamy?
If you lose the title or the Dragon an event fires that gets rid of the heresy
For the R+L=J submod there could be an exception made for R
Even after adopting the Faith of the Seven the Targaryens continued to practice polygamy, up until the dragons died out and they no longer had the power to enforce it.
What if there was a "Heresy" of the FotS, that only appears via event if you hold the Iron Throne or Kingdom of Westeros and if you have a Dragon, that allows for Polygamy?
If you lose the title or the Dragon an event fires that gets rid of the heresy
For the R+L=J submod there could be an exception made for R