Silver lining time.... count your blessings.. she took time with her kids.. and YOU didn't have to deal with them.

You have to try to focus less on "winning" with his EX.  Yeah,... I know.. she doesn't easily give your DH extra time when he wants it.. I know she is a pita to your DH and talks down to him and doesn't think he is capable of fully caring for his kids (but with things like that ER visit.. I kinda get where she may be coming from.. as he doesn't always make good calls).  But,  unless it impacts YOU.. you should try to let it go.

So.. unless she is trying to come in your home.. or take more money than she is due.  I wouldn't care what arrangements that your DH makes with his EX about the kids unless it interferes with your plans. Yes, your DH will have to deal with her.. for longer than 6 years I'm guessing too.  But, sometimes people just take the path of least resistance.. and for your DH that may mean that she "gets her way" more than he does.. but in the end.. you get the kids LESS.. so I see that as a WIN

Look on the bright side you got a skid free weekend, and if your DH feels taken advantage of that's on him. Last I knew he was an equal opportunity parent in all of this, just because BM uses her GUBM status doesn't make him any less a parent. It's been his choice to sit on the sidelines and let her run the show.

It's so frustrating when it seems they are talking out of two different sides of their face, isn't it?

There are a whole slew of reasons for this type of behavior but from what I've seen (in the most general sense) it amounts to old habits die hard.

A lot of former couples end up in the same patterns that killed their marriage.  It just carries over into the divorce.  That is how they relate to each other. 

Add in some hurt feelings and a failure to emotionally divorce on one side or the other and it just keeps getting uglier.

Fantastic when at least one can recognize and acknowledge the situation.  It could take months, years or maybe even never happen.  

I know you've tried time and again to help your DH see the light so to speak.  I think he's so used to constant dysfunction and strain that it's a bit of a sick comfort to him.  It is familiar, what he knows, how its supposed to work in his brains.

Not that you need any advice but if you Google something along the lines of emotional stage of divorce it might help you put context to some of your DHs (and BMs) nonsense.

Just remember, you can only control you.  

Yep, let him handle BM as he pleases.  You've set your boundaries, which are fair and realistic ones, the rest is on him.

Most of the time, men act like this out of fear that BM will cut them off from their kids if they don't give in.  That's a real fear. Only he can deal with that fear, in the way that he thinks is best. 

In this instance, this affects you positively, you don't have to deal with his kids.

Don't pay attention to her she just wants attention. See, rude huh.