The Logan of it all

SO during my millionth rewatch I am finding the switch from Kortni being so happy and in love to being so cringed by him and then over him, etc so quick. I get that her friend and mom brought up this issues but that doesn't seem to be the straw that broke the camels back. I feel like we are missing something. Then what really drives me nuts is in the episode that Kortni talks to the cops outside the beach house and she tells them his name and he shakes his head and she says "I had no idea he was this crazy" and multiple times Nilsa and Kortni say "This is a small town" soooo how did she have NO clue about his reputation or history with the police? Idk just a lot of holes here for me!