Friends,

Time is slowly approaching. My workplace is sending me to a meeting. My ex is going to be there. What makes things worst...he's bringing his future wife with him!!!! (They got engaged on my birthday!!) I get dizzy with anxiety when I think of this.
Bumping into him will be unavoidable. The thing is that during our "apart" years, he immediately moved on with someone else while I've been single all this time. Although he was the one to break things off with me, for some reason he looks incredibly happy knowing that I'm alone in life.
He knows that I'm still alone. He's going to rub his engagement in my face. He's so arrogant. I'm sure he'll do stuff like hold her hand and kiss her in public, which are things he never did with me. Generally he was never affectionate with me the way he is with her. I really loved him but our relationship sucked. He was not nice to me.
I don't know to respond to this. How should I act? How should I function? Should I show what I really feel? Should I be emotionless? Should I pretend that I'm happy? Do I say "hi" to him only? Do I speak to both of them? Gosh, this will be so painful. To be honest, I don't want to speak to them at all. I don't even want to look at them. I know I'm going to sound immature here but.....too often I daydream that I'm big and strong and punching both their lights out!!!!!!! I hate their happiness. Yea, I guess I'm not a nice person, what can I say...
The sight of them will make me cry, I'm sure. How can I hold it together? THROW IN AS MANY TIPS AS YOU CAN!!!!!!!!!!!!! What would you do?