Dear Maia
I consider you a rock, who has been SO much help to me on these pages. I appreciate your transparency on this latest thread. None of us are perfect yet, myself included.
Please forgive my bluntness here, but what you did with your daughters is called "triangulation." This is a technique that draws others in and gets them to do our "dirty work." If you really had to know what your ex was up to, you should just ask him directly. You would then risk him telling you that it's none of your business.
Maybe it would help to back away and look at the bigger picture. You divorced him for some very good reasons, including him making you feel crazy at times. At this stage in your successful, hard-won recovery, do you REALLY want to be drawn back into his drama? What is the need deep inside you that drives you to care about his relationships? Are you still trying to rescue him?