One of the things about this place is that the same stories seem to repeat. I would suggest you give thought to some of the things that were documented on Irish's thread that I'm sure you have read. Your W hasn't done the "girls gone wild" thing to the same degree but there are similarities.
You want to avoid (I believe) being part of the triangle and dynamics between the kids and their mother at least in the long term. Just like you won't be putting gas in her car in the long term, you're not there to be her partner in parenting the kids.
Others who have perhaps dealt with this more directly might be able to chime in with more specific advice though. Since my kids are grown and had left home before things went off the rails I've never had to be involved in co/parallel parenting.
On BD H52, W50 T27, M26 S21, D23 BD-9-Mar-16 D-15-Jan-18 Final-19-Apr-18 I am a storyteller. The story may do you no good. But a story is never for the listener. It is always for the one who tells
