I totally get that! I have a VERY hard time accepting that someone I married, had kids with and gave love and support to no matter how he behaved (ok, not healthy but that's a separate matter) HATES me with a passion.
I am not at all comfortable with people being upset with me and try to please and keep everyone happy (well, less so now actually but I used to constantly).
I think that as a caring, good person it is hard to know someone dislikes us and not want to try and fix it.
But with your ex as with mine, the only way to have them not be angry with us was to continue to enable and tolerate totally unacceptable behavior.
Our x's hate us because we aren't there to deflect their anger and self hate on to anymore and they have to own their own stuff (or continue to deny it and drink even more)...
I don't know what the solution is to learning to be ok with the hatred they feel toward us because even today I experienced it from my xAH and it made me nervous and sad and unsettled...
You're a great mom and a healthy role model for your kids and your x's anger and hatred is not at all about you...