How do I interact with a guy who broke my heart at a house party coming up?

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5 mo
I haven't spoken to him in two weeks. He was a guy who i was seeing for a short period of time and completely broke my heard when he said he didn't want to be my boyfriend. I'm scared to see him this weekend at our mutual friends party. What is the best way to interact without looking butthurt or desperate or sad, etc.
How do I interact with a guy who broke my heart at a house party coming up?
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