We'll Always Have Summer by Jenny Han

It's been two years since Conrad told Belly to go with Jeremiah. She and Jeremiah have been inseparable ever since, even attending the same college—only, their relationship hasn't exactly been the happily ever after Belly had hoped it would be. And when Jeremiah makes the worst mistake a boy can make, Belly is forced to question what she thought was true love. Does she really have a future with Jeremiah? Has she ever gotten over Conrad? It's time for Belly to decide, once and for all, who has her heart forever.

The summer I turned pretty part one

It’s not summer without you part two 

We’ll always have summer part three