SUBREDDIT: r/relationships
TITLE: Me [18 M] with my Ex [18 F] of 1 year, she is attending a friends birthday party tonight and its making me anxious.
POST: -Using Fake Names-

Not going into detail with my relationship with Wendy, but while we were together she made out with a guy who promised her weed, lied about it.

Now has convinced herself it wasn't cheating.
Wendy and I were good together little to no problems. Before i found out she cheated Wendy wanted to be friends after we broke up but of course in most cases that is impossible. She broke up with me 3 or 4 months ago now.

She is attending my friends 18th, and i have no idea what to expect from her.

After most the people attending the 18th heard that she cheated they all condemned her and broke off all friendships so its a bit strange Wendy is coming. 

All i'm wanting to know is what to expect and what to be prepared for.
TL;DR: 
Didn't break up on good terms, don't know what to expect or how to handle seeing her at a party!