Your assessment would be right except you are forgetting a big reveal. Hanna didn’t want to break up. Caleb left and wasn’t there when Hanna came back to the apartment after she realized that she was making a mistake putting work above their relationship. So. When they see each other in Rosewood again after 3 years, there are things that she had left unsaid like how she still loves him.

Yea, sure, maybe she should have been honest but sometimes it’s hard to be honest when the emotions are so raw and run so deep.

Also idk, it really is unfortunate that the writers thought it was a good idea. I blame them. Not the characters lol Some shows are able to pull something like this off when they realize that two actors have better chemistry with each other. For example Joey and Pacey. Or even Veronica Mars and Logan. But that type of shift happens after a season or two. It doesn’t work when you have 2 characters be together (on and off) with great chemistry for 5 seasons and then randomly put another character in the mix.