There are two things that all abusers do well.
1] They identify some soft spot in you, and promise to take care of it.
2] They tell you they "only" abuse you because you deserve it.
Those two acts of emotional warfare create a powerful dynamic. If he does it right, he manages to create a dependency in you (he promised to make you better) coupled with a sense that you only deserve a horrible relationship and you're lucky to have even that. It may have been love to begin with, on your side at least, but by the end it's a cancerous need, very similar to harmful addictions like heroin.
Think about how many times you "tried" to make his promise come true ... he said he couldn't love you enough right now because you're too short, so you wore heels (
) you're too needy, so you shut yourself up, you're too serious, so you told jokes ... etc, etc, et bloody cetera. All false bargains, in hopes of a false promise. And meanwhile your confidence, integrity, even your entire self, shrinks away. You're all self-doubt and anxious hope :(
Then you break up, and look! He's in another relationship and it's GREAT! See, he comes good on his promises right enough! It's just that you were too crap to deserve it. He was right all along, you short, needy bore!!
No wonder it's thrown you. This lie, in fact this whole gift-wrapped box set of lies, yanks all your strings at once - the string you came with (which he metaphorically used to tie you down) and all the strings he added while he had you. Shake 'em off. He's doing exactly the same to her - undermining her on the strength of an empty promise.
He's got his victim; you've got your freedom. More to the point, you now have yourself back. That's all the revenge you need 
Give yourself a hi-five.