Perhaps they can tell that everything your ex, their mom, does bothers you and they feel like they are getting caught in the middle.
Just a thought. I'm not in your sitch. I'm not sure what my stbx is doing in her free time. For the most part, she hasn't thrown any of it in my girls' faces. There are a couple of times she's ditched them at MIL's so she could go partying, but nothing to the point it's worth complaining about.
Me: 47, Ds 17-13, D final 6-11 http://tinyurl.com/yk4e2tz http://tiny.cc/thread2 http://tinyurl.com/ydtphqu http://tinyurl.com/thread4 http://tinyurl.com/3sm78k6 http://tinyurl.com/thread6
