Whenever I watch Jess episodes I’m left wondering...
I’ve seen people make the defense that Rory saw beyond the stupidness. That when Jess acted out Rory defended him because she knew how smart he was and knew that the Jess everyone saw wasn’t really him. My opinion is that Jess was a teenager. All teenagers act out. If he didn’t grow up and out of it I would have been worried, but he did.
It’s not just stupidness and acting out. He treats her badly and doesn’t respect things that are important to her (like her family or her hometown).
I also don’t think we have enough time with “grown up” Jess to really know how much he’s changed. He’s certianly more responsible, but we really have no idea how his behavior/the way he treats people has changed.