I would say, for your future, do whatever it takes to ace that job interview. Even though you are dying inside.
Let family heavily look after the kids while you prepare, stuff away all the shock and pain just for the short term (even pay for an emergency counselor to get you through it)
Obviously this is an awful technique, but if yours and your children's future security is improved by getting the job/promotion, I really think you should just absolutely power through. And then recover after that hurdle.
Of course that's easier said than done... He's a literal piece of shit. An alternative could perhaps be to tell work about what's happened, and see if they can make any allowances with the interview process, or delay it a bit?
But in the cold light of day you will be glad if you have more autonomy and a better financial situation going forwards, as impossibly hard as it will be to get through. Don't let him fuck up yet another part of your life, I really hope you can compartmentalize it and have a great interview. It's a gift for future you, when you've healed from the walking anus that has done this to your family.