Is this a fair marriage? Or am I missing something here?

The kids are not mad at you. They are upset about the change. Once time goes on you will prove to them that things can be okay that you and your ex are apart. But as far as you and your relationship with your husband, you did a good thing. And it is good that you waited out your childrens childhood to make your move but now is time for you to be happy. It is expected that your children be upset. As time goes on things will get better. Your ex sounds like a douchebag, good for you for breaking free.