ESH
She is the asshole for ending the relationship on that specific day, AND for jumping straight into a new relationship. Thats pretty cruel AND cold. I think she probably waited too long to end the relationship. And this is what you get. She is emotionally checked out when it comes to the old bf, and doesnt care how it will make him feel. Maybe if she had broken up 6 months ago she would present better. But sunken cost fallacy, and especially when friends also put weight on the time already invested is very difficult for people to get past. If she had left him one of the earlier times when she mentioned she wasnt happy - would you have called her disloyal. Did you encourage her to stay those times?
You are saying you told her you dont judge, but you are judging her. The loyalty comment is the worst one. Dont they both deserve loyalty. And if someone is unhappy in a relationship and ends it, does that mean they arent loyal? Would you want her to place loyalty to their relationship above loyalty to herself AND to him, as a person deserving of a partner who wants what he can give and doesnt long for someone or something else. I just think the comment is weird and Im not sure what your motivation was when you were saying those things. Saying; Look Im not judging you, but here is my judgement LOL.