I don't know anything about your finances but you don't ahve to buy him a new car. It can be one that rungs well and will give him a year or two.
I have nothing to say to the rest but I sure do understand your anger. I think you are OK to be angry and I think not being angry would be odd.
That being said, don't stay in that anger place for a long time. Use it to get past it.
As to your ex.. if he wants to make amends tell him this, "Don't make amends with words. Just send money!"