Short answer: hell no! This SEEMS to get complicated because of your children, who like NX and the new supply, and say to you that you SHOULD be friends with NX/new supply. How do you handle this? And, your friends and family think you should as well.
They say "let bye gones be bye gones", right? My wife and I have gone though this. Here's what we told them....YOU can be friends with them, if you'd like, but we will never be friends with them. And, you have to tell them the reason, in an age appropriate manner.
Absolutely not! What they did was absolutely wrong, and the N is a liar, abuser, and cheater and the fact that you have managed, after a huge amount of pain and heartache, to recover, doesn't change anything.
You have the NX to thank for the terrible financial hardship you endured, and the divorce/split, the sleepless nights, the therapy you paid for...and the NX/new supply wants you to sweep it under the rug and whitewash them? Not gonna happen.
That would be like the NX DELIBERATELY driving a car with you in it into a tree, severely injuring you with pain that will never fully go away, causing you years of recovery time, and expecting you to tell everyone what a great driver NX is, and then, to be the NX's friend and act like it never happened. I will NOT pretend like that because I had to pretend everything was OK when NX and I were together and I'll NEVER do it again.
You still have to deal with the injustice that most people, perhaps even your kids, treat NX as if NX hadn't done all the rotten things they did. Yes, but you can't control that. However, standing your ground and moving on with your life and being happy is how you recover a real life again.
You have a new and better life now. NX tried to destroy you and didn't succeed, so you're the victor in that battle, but there is no reason for you to act in a fake and phony way just because other people, especially your NX, wants you to. BE TRUE TO YOURSELF and what you know to be your truth.