WEll - first of all, Kimmerz, you know you have to take everything your kids tell you with a grain of salt. What you're hearing may or may not be the whole picture.
I know you probably don't want to talk to your ex about it (lord knows I avoid talking to my ex as much as possible) but perhaps this is a time when you should buck up and just give him a call. Couch it in a non-threatening way if you can. Perhaps "Gee, Ex, I really want your time with the girls to be a great experience for all of you. They've been telling me that they feel excluded by OW. Do you think there is anything that can be done to foster a more comfortable relationship between them all?" (Try not to throw up in your mouth a little as you say this).
