When Does Jeremiah Cheat On Belly

So, picture this: I’m scrolling through Twitter at 2 AM, half-asleep, when a tweet pops up: “Wait, Jeremiah cheats on Belly in the books???” My coffee—yes, at 2 AM—almost went flying. I had to sit there, blinking at the screen, because how could the sweet, guitar-playing, loyal Jeremiah from the show do that? Oh, honey. If you’re only a show-watcher, buckle up. We need to talk about the timeline that makes you question everything.

Here’s the deal: in Jenny Han’s Summer I Turned Pretty books, Jeremiah doesn’t cheat on Belly during their main relationship. Wait, what? I know, I know, the rumors are messy. But the infidelity happens before they ever get serious. It’s like that friend who tells you they “cheated” on their ex but only after they’d already broken up—technically true, emotionally devastating, and super confusing.

The actual cheating moment is during the second book, It’s Not Summer Without You. Belly and Jeremiah hook up at a party when she’s already sort-of with Conrad? And then, later, Jeremiah makes out with someone else. Hold up. It’s complicated because they’re not “official,” but the emotional betrayal is real. You feel that sting even if you want to defend him.

But let’s get specific: the big “cheating” debate centers on the third book, We’ll Always Have Summer. Jeremiah and Belly are engaged (yes, engaged—don’t ask, it’s a whole thing). A girl named Lacie shows up, and Jeremiah kisses her at a frat party. Boom. That’s the smoking gun. It’s not a rumor—he admits it, and Belly finds out from Lacie herself. Ouch.

But Why Does Jeremiah Do It? (And Why Does It Feel So Out of Character?)

Here’s where it gets ironic: Jeremiah is the “nice” brother. The golden retriever. The guy who brings you snacks during a fight. But the book shows his deep insecurity—he always feels like second choice. When Belly chooses Conrad first (even after they’re engaged), Jeremiah self-destructs. Classic move, guy. He kisses Lacie because he’s terrified that Belly will leave him, so he leaves first. It’s dumb, it’s human, and it makes you want to shake him.

The timeline is crucial: this happens after Belly calls off the wedding. Wait, what? No, actually—the kiss happens before the wedding is called off. It’s a domino effect. Belly discovers the kiss, chaos ensues, and the engagement implodes. Jeremiah’s cheating is the match, not the whole fire.

The Summer I Turned Pretty Season 3: Did Jeremiah Cheat on Belly More

Side note: If you’re like me, you might scream, “But they weren’t married yet! Does engagement count?” Look, if you’re engaged and you swap spit with someone else, it’s cheating. Period. But the book leaves room for interpretation—Belly also kissed Conrad in the same timeline. Oh, the irony. Everyone’s making bad choices in this beach house.

Does the Show Change It? (Spoiler Alert: Yes)

Okay, here’s the good news for show fans: the TV series has already changed things. In Season 2, Jeremiah tells Belly he “wouldn’t do that” to her. The showrunners are clearly softening him. Thank goodness. They’re setting him up as the stable choice, which makes the cheating plot harder to translate. I’d bet my iced coffee they’ll either skip the Lacie kiss or turn it into a misunderstanding.

But if the show does follow the books, the drama is coming. And it’s going to hit. You’ll go from “aww, Jer” to “wait, what did you just do?” in one episode. Prepare your tissues.

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What Does This Say About Belly and Jeremiah’s Relationship?

Honestly? The cheating moment exposes the cracks that were always there. Jeremiah wanted Belly to choose him first, but he never felt secure enough to trust it. Every time she mentioned Conrad, he flinched. The kiss wasn’t just betrayal—it was a symptom of deeper issues. Unpopular opinion? Maybe they were never meant to be long-term.

Still, if you’re team Jeremiah, the cheating feels like a personal attack. You want to defend him, but then you remember: he’s a teenager. Teens do stupid, selfish things. I mean, I once “cheated” on a high school boyfriend by holding hands with someone else. Cringe.

So, when does Jeremiah cheat on Belly? In the books: during their engagement, in the third book, with a girl named Lacie. In the show? Too soon to tell. But if they follow canon, brace yourself for Season 3 or 4. Until then, keep your love for Jeremiah—just know his hands aren’t entirely clean.

Now, who else is rethinking their Team Jeremiah merch? Just me? Cool.