A few thoughts:

- they express anger to you because you're the "safe" parent. They can't express it to him for fear of losing him.

- initially they may buy into his "reasons" why he " had" to leave, or may feel like somehow you failed to do something needed to keep the family together. Don't worry, eventually they will come to see, based on your actions and his after the divorce, what the truth is.

- when she talks about her communication with her spouse, she's looking for reassurance that this couldn't happen in her own marriage. No need to disabuse her of this notion right now.

- don't discuss your ex with her anymore. My kids HATED feeling like they were in the middle. Don't send messages through the kids, even about simple things like holiday schedules. Don't say anything critical of ex in front of them.

Stick to the high road, become their rock, and set an example of vibrantly moving forward in your own life. They need to know it's going to be okay and they are looking to you to set that example. Let them know you have their back.

It's taken a few years, but my middle child, who was closest to ex, now really gets that I am the parent who can be relied on.