Seriously?

For the year that I have been around, the visitation situation with TD has been flexible to the point of driving me crazy.  I'm glad TD and the ex can communicate relatively well, but I like structure.  It's hard to make plans for dinner, friends, trips, well everything when you never know if you're going to have a 9yo in tow.  I enjoy having her, it isn't that at all, but it does change what you can and can't do.  Not like you can take said 9yo to Beerfest Oktoberfest (which is coming up this weekend and I'm sooooo excited about).  You have to plan for these things, which brings me to the events of this past weekend..........
It was our weekend.  That should be the end of the conversation as far as I'm concerned.  We picked TD up from school on Friday and had a great night Friday night.  TD said she would like to pitch a tent and sleep in the front yard, which sounded like fun to me, so that's what we did.  NG's bachelor party was Saturday night, so he slept in his own bed in preparation for the long night ahead.  So it was just me and TD, in a tent, on an air mattress, in sleeping bags.  We had a ball, it was so much fun.  She's fascinated by stories of my childhood, I think because they usually involve my brother and she's an only. 
A couple days ahead of time, the ex asked NG if she could have TD for a birthday party on Saturday.  Turns out, after asking TD about it, that its the birthday of a friend of her mom's kid that TD doesn't even like.  NG tries to play nice, as his nickname would indicate, so she comes and gets her at 11 with the plan being to return her at 2.  I ran some wedding errands, came home at 2:30 to no TD.  Apparently she's being returned at 4 now.  Come 6:00p NG finally just goes to her mom's and picks her up.  In my head, this is insanity.  I needed to take TD shopping for rehersal dinner clothes and shoes for the wedding, by the time she's home and showered and stopped crying, it's after 7.  Why, you ask, was she crying?  Because the ex is an idiot. 
At what I can only assume was a time after TD was to be returned to us, her mother leaves with her friend (the mother of the birthday boy) to go shopping, leaving TD with an 11yo boy, an 8yo boy, and their dad.  Being a child therapist, hearing the stories of so many victims of child molestation, this disturbs me quite a bit, but what do I know, I'm just the step.  Anway, so mom leaves and TD asks the dad if they can go to the park.  This was a mistake on her part since she knows she's not allowed to go without an adult.  Given that mom left her with this guy who doesn't know the rules, he said yes, and off they went.  A 9yo girl with an older and a younger boy, to the park, in a city, unattended.  Awesome. 
By the time they get back, mom's home and screaming at TD.  Takes her prized video game that she had just gotten that day, and sends her back to us sobbing.  Super. 
This is the end, theoretically, of the interrupted weekends.  Its something ridiculous like the 4th visit in a row that mom has found some reason she HAS TO HAVE TD to do something.  Like seeing a play that was in town for 3 weeks, that was last time.  Seriously?  Maybe that's what happens when your 9yo daughter is your best friend.