This is late in coming, but I think you giving $700 per month was the dangerous precedence. I hope it doesn't bite you in the butt in court. Thankfully she has no lawyer.
I think most of this is reacting out of fear. She probably is afraid of losing the kids, either their affection or actually having you get them more than 50% (eventually). I think some of this is defensive posturing. Also, she knows the money tree will soon stop producing fruit (aka, you won't be giving her more money) and she's grown accustomed to it (her bf has also...that was really a bad idea. Two of them couldn't support themselves without your help? Please). So, let this slide like everything else. No more money buddy. The mediator told you plainly that C.S. wasn't necessary. Alimony certainly isn't. So quit with the money. I understand your reasons, but the money issue should be a new boundary.
Me
In the end, it's not the years in your life that count. It's the life in your years. Abraham Lincoln
It is hard to fail, but it is worse never to have tried to succeed. Theodore Roosevelt
