Love how often the main characters of Trigun Stampede are just full-body flailing through every episode. Are they running from bullets most of the time? Sure. But they also manage to trip all over themselves, stumble down each flight of stairs, get bodied by moving vehicles (sorry Wolfwood), and slapstick their sorry asses in and out of every NON-life threatening scneario just as often. It’s peak television.
Does Yuri also think that Yor was a sex worker?
Everyone else in Yor's life seems to believe she was. I'm sure Yuri would have taken any lie Yor told him about her work at face value, especially when he was a child who wouldn't understand. But he isn't stupid. And unlike with his suspicious about Yor's marriage, everyone else in his life also believes this. Yuri probably put the pieces together when he got older which only made him more overprotective.
This would recontextualize a lot of Yuri's actions. From his perspective, his sister was a victim of repeated child exploitation from unknown men. She purposefully didn't tell him and Yuri wasn't able to do anything. Now a strange unknown man has apparently been married to his sister and she didn't tell him? It probably felt like the same thing was happening all over again. But this time he could do something about it.
That's why he did a complete 180 from trying to find Yor a boyfriend to trying to have Loid executed. Why any suggestion of them being intimate sets him off more than anything else. And why he is so focused on eliminating scumbags from their country.
I think this was hinted at in Yuri's very first appearance. We have never seen him behave as violently as he did in his introduction scene. Yuri started off his interrogation with Mr. Hayward pretty calm and jovial. But when Mr. Hayward says that he was "spending money on ladies" and claiming that Yuri should know what that's like as a man, Yuri explodes. He starts sadistically torturing Hayward while screaming about protecting his family. To him, this man was as bad as the people who took advantage of his sister.
And it can't even be argued that it was the treason that set him off. He did not have the same reaction to the photographer, and Yuri even tried negotiating a quiet surrender with Twilight. He wasn't delighted to hurt Twilight or put the photographer in prison like with Hayward. Nor did he mention protecting his family. These guys were doing much more treason yet they didn't elicit the same personal response and sadistic rage.
