Surely you left because you knew that was the best thing to do for yourself, as well as your children??? and from what I can tell, you definetly made a grand choice. So whats to feel guilty about there?? I really do know how you feel though, I did the same.
Your DC will not hate you!! Do you know if your ex ever bad mouths you infront of your DC?? This is one thing I make sure I never do (although it's soooo hard) I want the girls to never hold anything against me so I always refer to him as "Daddy" and speak about him in a positive tone. I know exh and his mother have posionous tongues when it comes to me, I just let them crack on.
This will all come to bite your ex on the arse in the future I'm sure.