The wedding is called off in The Summer I Turned Pretty season 3 before Belly goes to Paris.
Belly and Jeremiah become engaged earlier in the season and begin planning a wedding. Their plans reach a crisis in episode 8, “Last Kiss,” after Jeremiah learns that Belly still loves Conrad and confronts her about those feelings.
The planned wedding is canceled immediately before Belly decides to leave for Paris. She sees Conrad at the airport but boards her flight without approaching him. In Paris, the exchange-program problem and the theft of her backpack lead her to remain in the city instead of returning home.
The canceled wedding should not be confused with the wedding rehearsal dinner, which takes place earlier and is shown in the same episode. The memorial garden ceremony is also a separate event involving Susannah’s memory. The finale later resolves Belly’s romantic storyline with her reunion with Conrad.