Have you ever been rejected by someone only to heal then walk down the street and see them with their new partner? I live near my ex and keep seeing him at public events--we go to school together--with his new girlfriend.

I want to strangle him because he said we couldn't work because he needed to be alone (! )
I want to confront him because I feel angry beyond words
I can't even look at them because I feel sick to my stomach
I want to act like I don't care... I want to nonchalantly approach him and prove that I am not remotely disturbed but most of all--it hurts so badly. I feel like someone just kicked me in the stomach. How, how do you get over this? We are required to go to a number of events for a class so avoiding him is impossible. I have no idea what to do--I end up feeling like every time, esp right after getting myself confidence back up to normal.