I don't feel sorry for him at all. Her husband started having sex with another woman in front of her without consent from her.
Hell, he deserved to be NTR'd.
Are all Sages asshats? Between this one, the one from "I'm a Villager, so what?", and "I Was Kicked out of the Hero’s Party Because I Wasn’t a True Companion" it's becoming a rather stable trope.
But then again, I've seen many shows and novels that portray Sages as insufferable know it alls. So...
Targeting Rain could lead to two scenarios that are equally bad.
1. Sansui goes berserker mode.
2. What Sansui cherishes most is rain, so if he goes with her if she leaves, they lose a major fighting force.
Either way, letting a fat suspicious noble from another country into your politics...
@Nk9bjP4A He was as powerful as a seasoned Knight when he was a child and defeated an enhanced Minotaur as a student that even his whole class couldn't put a scratch on. Remembering martial arts from a past life, continuing that training while going to a noble school that trained him more, age...