I wouldn't even cry. I'd be in shock just watching him run or walk out. I'd stand there for a few mins looking at the exit where he walked out. I'd walk out, go home, and keep quiet. Wouldn't answer texts or calls and I know he'd try to contact me to say he regrets it, hes sorry, to meet up, yadayadayada. I'd move on silently yet painfully. There's no forgiveness for that tbh and this is literally what I do when I am really hurt, I can only imagine the extent of the things I just listed if I was left at the alter.
I'd try to find them and give them the biggest bitch out of their entire life. Then I'd dedicate the next year of my life to destroying theirs and everything they love. Then after that was done I'd never talk to them again and let them think about what they did while I went out and got the finest D available and enjoyed the rest of my life without them
I'd be devastated, but then I would realize why would I be devastated who had the audacity to leave at the altar?! Then I'd focus my devastation on all the money I wasted.