I am so sorry to hear about what xH is up to concerning your kids. That sucks.
You have every right to be mad and every right to get your lawyer to nail his a$$. Your kids should not be over there spending the night, period. Even if they had their own rooms.
Hang in there. I am getting different but similar crap concerning the kids from my Ex. No OM yet - she just does not want to give them up for me to see them.
Thank God for the divorce decree.
We give them what they want yet they still continue to hurt us. And they hurt our kids. How can they be so cold and so blind not to see that the kids are in the middle of their actions????
