I am not a counselor but I am a special ed teacher for children with emotional impairments. Part of the problem is that D9 is trapped there when she is with him. She has no way out. I am also not sure with OW acting the way she did when H and you were on the phone last night that OW is as "nice" as she pretends to be. She sounds as if she plans to try to replace you and this will create anxiety as well. One thing I can say is that if OW runs the show as it sounds, they may not be asked back. A little reality for H and OW is probably a good thing. Hard to carry on with the fantasy life when you have two sets of children and they don't share in the fantasy you have created.
I will pray for you and your family. What is wrong with this world anymore that these MLC WA's have to put their own selfish agenda ahead of the children they brought into this world with a responsibility to protect.
I have to say your H and OW make me very angry. Please get D9 into a counselor as soon as financially able and ask the counselor about sending her halfway across the country for weekends. She may not be ready for this for a while.
Everything happens for a reason, maybe Dad needs to find that it isn't better out there, he needs to realize how good he had it here. Maybe he will find God and that is the most important thing when he finds Him he will know he is supposed to come home.