Depends. Given a chance, I will never ever want to see her
again. Especially when she is holding on to another guy's hand. I
would not want to risk a struggle with my emotions.
But then again, when I saw her back in my college 9 months ago, I
smiled. She looked down and ignored my presence. She was alone at
that time anyway.
Given your situation, right now I would say I will walk up to her,
give a smile and walk away trying not to think of anything else. At
least, that smile is to reward myself for spending 2 years in
overcoming her. And at least, I am still standing.