As a suggestion, be your own Hero, not the one someone else defines. I have the utmost respect and appreciation for everything RCR has done, but her writings are guidlines. Some of them were her experiences, but that doesn't mean it will work for you, apply to you, or be your end goal.
What do you want to see in the mirror in a year, three years, five years? Do you want to talk to your X as if he'd never treated you as he has? (Valid choice) Do you want to be civil for the sake of S? Do you want to never speak to him until he becomes someone you want to be friends with? Do you not give a fig and simply want to take care of yourself and S?
All you can do is be your own hero. I tried being kind and interacting with my mlc spouse when he was at home. I got a job where I could support myself and the kids after being mostly a SAHM for 18 years and he decided he was done out oF nowhere. I paid the kids insurance, all their expenses (no child support from their dad) drove S back and forth to school getting up at o dark thirty to do so, came home, helped with homework, made dinner, did every freaking thing I did as a SAHM PLUS worked 50 hours a week. Got S through high school and D through college, sometimes grammar and spell checking papers at 4:30 AM (dyslexia). Helped get D get launched at her new job. Kept S out of severe depression when the first college didn't work for him. Kept my house, reroofed and got it painted all on my own (this was not cheap-concrete tile roof). Kept good relations with ILs. Pulled myself up by my bootstraps and keep moving forward. I'm my OWN freaking Hero. Maybe I couldn't save my marriage, but that doesn't make me, and countless others here our own brand of Hero.
Define what your own Hero is. Then do that.