I mean, you can't necessarily blame her completely for that. She loved the man, and appears to not moved onto him. She saw that he gave up that life, and how could she have known that someone would tweet about his affiliation? The guy was just torn because he witnessed his life disappear in the snap of a finger. You're basically critiquing the movie for characters being human. Lastly, her job was there. His friends, and family were there. He never denied being a Yakuza, in fact, he probably wouldn't have left if the boss hadn't told him to. It's the fact that the boss knew he was fiercely loyal, and had to tell him. It makes sense as to why he didn't leave. I respect your opinion, just putting my own input.