I think the thing that most often is overlooked is the difference in priorities which, while it might have not been the primary reason why Rowan did not ask Daenara for help, is also a factor.
Rowan wants to save his wife. However, if you tell fantasy pope with tits that the literal children of the devil are trying to conquer the world, and if said fantasy pope with tits believes you - well their main concern will not be saving your wife, but
murdering said literal children of the devil.
The Church tends to focus on the big picture. Individual lives are collateral.
Says you.
Sure he has friends, but mobilizing an army to march half the continent:
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Is a big favour to ask for, particularly when you get stonewalled by Werden.
If Rowan kills Jezera right there, he can save Alexia basically without any opposition.
If Rowan ignore Jezera, he may find Alexia, and he may even get her out of the castle - but getting to safety from there? That's a much harder task.
High risk, high reward. It didn't work out, because the game needs to happen