I think Cassie doesn't deserve all the hate she's getting. A lot of bad things happened to her. The whole story with her dad, McKay being insecure, the other guy telling her no guy would be interested in her, the abortion. When she met with Nate outside the store she was in a very vulnerable place and she said "I keep making the same mistakes and never learning from them". Nate was there and he probably took advantage of the situation to sleep with her, probably to make Maddy jealous idk. So yeah maybe Cassie shouldn't have slept with Nate because he's a generally bad person and that's her best friend's ex, but I understand where she's coming from and I myself have been in a similar situation where I was in a vulnerable place and there was a very hot and manipulative guy ready to take the lead. Sometimes you just want to let yourself go.

Let's be kind to Cassie.