cal’s best friend, tate, is her ex boyfriend. they didn’t have a very good relationship, especially towards the end. when tate finally had to break up with her, cal knew he was a dick for it and helped comfort her. they were friends before, and they get closer and closer till they can’t stay away. he started to fall for her very quickly, but knew they shouldn’t be together because of tate. once they are together though, they know they need to keep it from tate or he’ll freak out.