I can't imagine what that feels like to you kids. I know you wish for better for them.
My D15 has had lots of anxiety and acting out behind all of this and currently seems to be making better choices. D18 has never said a word. I watch them both and use differnt strategies for making sure they we have as much communication as possible (they are after all tennage girls). My oldest writes (stories etc.) the younger one to some extent is more willing to talk or write me a letter. I'm sure you have things that you do with your kids that work.
I know how hard it is for you to watch. My heart goes out to all of you.
Are kids resilient? Sure. How much are they damaged by this....well that remains to be seen.
I have a friend whose Dad had no contact with them for years (alcohol in his case). Recently, she has developed a tentative relationship with him. She is in her 40's. Better late than never I hope.