No way. I made the mistake of getting back together with him after 7 years, thinking he was different, and found after time that he was actually worse than I had remembered him.
We have been getting along mostly civially the past couple of months, but that is because I've accepted he is a UAV and incapable of being anything but that and simply do not engage anymore. I focus on simple conversation about the children, and put anything pressing regarding divorce/anything else in writing. If he calls irate, I hang up. If he texts back some BS, I ignore, but save the text if ever needed in the future.
I think it's possible for some to get "better" for a time... but that is the key... for a time. It seems to never take very long for them to fall right back into their natural ways of abusing others. I think it would be especially hard for a person to "stay better" being with the person they had abused for any amount of time... it's even more easy to fall back into old familiar patterns.
When EX is being "good" I'm happy that he is taking care of the kids the way he should for that time. But I know it never ever lasts. I am so so so so happy to not be on that roller coaster/horror ride anymore.