The twins will never agree to any submissive scenes... As long as Rowan is their servant.
So, one day for sure.
Rowan was always submissive even before he met the Twins. If you people remember the Noble lords treated him like trash and he was okay with it more or less because that was reality. He deserved to have a better life for his actions but in the end he just became a humble peasant in a humble village. Him serving the Twins is way better in every sense. Minus the death threat should he fail. He lives in a castle, wears better clothing, he is third when it comes to power and influence and has access to all the pleasures life can provide - his wife, entertainment, connections, other women (or men depending on the player), exotic food etc. He even can fuck his own bosses should he want.
This is a huge step up from what he had before so in my mind there is very little to make him rebel unless his naive morality gets in the way of his thinking or he is indeed just power hungry and wants to be at the top of everything.
Jezeera is indeed manipulative but she had a point. They lived in a Feudal society where talent and skill doesn't matter, only your birth. Sure their upcoming brings a lot of bloodshed but that is to be expected when a new order is taking over. There are a lot of mortals out there, intelligent and skillful that see the merit of their rule and stand by their side. Personally i side with the Twins because they have a point. I don't care who rules over me as long as he/she is better than the previous ones.
If Rowan is in a open relationship he can very well in the future snu snu Jezeera and create her an heir you siring the ruler of the world.
The only way the Twins would submit to Rowan is if he becomes stronger than them. No other way.