"I used this as leverage with my current employer"

That seems to be the way of things in every field. Jobs for sure, but also if you have an insurance policy or a cable tv subscription or even a credit card.

The moment you say you are leaving, you get a better offer you can't refuse. I think every field of human endeavor abuses the good nature of folks who choose to stay put and don't make waves.

It's a shame, but a lesson worth learning. :)