I respectfully disagree here. Putting the kids in the middle of this is not at all the right solution. My RAM and my father who divorced when I was 4 never spoke to each other and hardly had any interaction while I was growing up, even when dropping me off or being in the same room together. It put me in the middle and made me feel responsible and created a problem for me in terms of feeling like I had to "heal" things. Also, created a situation in which I didn't feel comfortable talking to either of them when I was having issues with them. Not comfortable at all.
I think the better solution is to take other people's suggestions on working on you, but to have a quiet and private conversation with your husband about keeping the conversations and interactions civil and friendly when in front of the kids. No put-downs, no criticisms, no talking about the issues in your relationship. Your kidlets need to know regardless of whether you stay together or not that you as the parents always hold their well-being above each of your own.
I am not a mom yet, but having grown up with that kind of childish behavior, it is something I am determined to not do when I do have kids.
Originally Posted by
MeetJohnDoe 
It's great you want to be the best person you can be. Stay strong. Not sure how old your kids are, but I'd minimize the time you have to interact with him. Have your kids answer the phone when he calls. Stay in another room when he comes to pick them up. Don't deal with him. Anyone who puts you down to prop himself up is toxic, someone to be avoided. Hopefully in time he will become a better man, recognize his weakness, his past bad behavior, and you can renegotiate a mature adult relationship. But in the interim, don't give him the power to make you feel bad.