There isn't much point in beating a dead horse, but Noah is doing way too much in the sequel. Calling someone's school because they won't answer your text messages? Just call her phone! If she doesn't answer, take the hint, buddy. Elle's decision to give Noah space without letting him know she's doing so is admittedly childish, so I don't blame him, but he could take it down a notch. He should also know better than to think that lying to Elle about hanging out with Chloe will work, but he's a college freshman, so I'm not surprised. If someone makes the point of asking, "Who did you go out with," chances are they already know the answer and you're walking straight into a trap.
To Noah's credit, he isn't the one who cheats in the relationship, so he gets a pass in that case. He knows that bringing Chloe to Thanksgiving dinner would make Elle think their relationship is something romantic, but he's in a petty mood, so again, I can't blame him. I hoped that his parents would sit him down and have a conversation about how you shouldn't lie to your girlfriend about earrings they find in your bedroom, but the parents of The Kissing Booth have a very hands-off approach to basically everything since they barely speak up.
When Elle tells Noah she suspected him of cheating because of his "past," I genuinely thought they would break up in the end. True, their problems stem from an inability to talk to one another (because they're children), but the fact that Elle so easily brought up whatever past indiscretions Noah has had is a sign that to the core, she doesn't trust him. That's why it's so easy for her to believe that he's cheating on her with Chloe. It's easy to find evidence of someone's bad behaviour when you already believe they're capable of hurting you. Despite Elle telling Marco that he isn't "the one," I don't think Noah is her one either.