Oh sweetie I am so sorry...fear for your children's welfare has got to rate up there as the one of the truly scariest things in life.
I have no professional expertise in either psychology or law, but this all sounds terribly sick and certainly unhealthy for the children. And maybe actionable, if there is any evidence of the sexual content. I'm going to just throw out some random thoughts:
Have you talked to your L about action? Would your therapist support you in an affadavit stating that OW's behavior borders on sexual abuse (if it does, I don't mean to suggest that the T make something up). Could you get a restraining order in regard to the abusive emails--is it stalking?
I don't want to overreact but if it were me I would take action to keep my children physically aware from her unless supervised by an independent third party.
I'm sorry MTN. I am beginning to understand how awful it is when the OWs start to become "permanent fixtures" in the kids' lives. I agree with you, and I understand what you meant when you said this is the worst part of the D yet.
I wish I could be more helpful. You are not alone, even though it feels that way.
