I can’t understand the cruelty

I recently divorced my husband of 18 years due to his alcoholism and my discovery of his affairs. I am a good, kind person. I’m thoughtful, I was a good wife, I did everything for our family - plus I’ve always worked full time, contributed more than 1/2 of our income, etc. People in my life (other than my ex) are so supportive and tell me that I’m an amazing person, a great mom, etc…..I KNOW I’m a good person so it’s hard to understand why I’m being treated this way.

I cannot understand how the person who was supposed to have loved me can be so shamelessly cruel. He refuses to pay a dime of child support for our kids or even do the mandatory sobriety testing in order to see them. He is horrifically mean to me - essentially I am the villain in his story. I know that I am doing the right thing by keeping my boundaries but do people in the thick of alcoholism even realize how cruel they can be? Do they feel bad about it? Do they ever try to make it right if they get sober?

I have been diagnosed with CPTSD, anxiety, depression, a sleep disorder and now an autoimmune disease as a result of stress and trauma. I do not think I can possibly live the rest of my life (or the next 10 years) this way, but we have kids. I fear that this will kill me before it kills him. I don’t know what to do.