bro I don't chime in much lately because life has just been a blur lately but this is probably my favorite thread to follow so I'll throw in my 0.02 cents
It's ok to tell the kids and their puppy dog faces that they won't be seeing mommy on your birthday just like they won't be seeing you on her birthday if that's what she arranges, don't worry, they will understand, they know how to work you because you are such a good dad always taking care of them that they know you will probably not refuse them anything.
As for her nastygram, I would have told her "stop emailing me" plain & simple. She is projecting, as far as her great life and great new relationship because I really don't think it's as great as she says it is, when something real is as good as she's making it out to be, you usually don't have to brag about it or talk about it openly, she's trying to make it out to be something spectacular and it really isn't and she knows it, you aren't pursuing anymore and it's wrecking the dynamic you have between you two. She is used to you pursuing and you're not, she is used to you arguing and you're not, you're probably acting indifferent to her and she always pictured you wallowing in self-pity and pining away for her until the day you die and you aren't doing any of that and that's what pisses her off. I'm glad you told her that it wasn't a good time to come over in the morning, get used to do that and as for the 3rd party location, just say in simple terms "NO I won't be doing that anytime soon, you're a brat and you're getting all angry because you don't get your way with me anymore and I don't care enough to waste my energy in these useless arguments. You drop them off here, I drop them off there, no one says we have to discuss anything during the exchanges. I'll be an adult, you try to do the same thing" ... and that's it.
Stand up to her bro, you're allowed, don't let anyone disrespect you, it's not just a lesson for you, it's a lesson for your kids as well, do you want your son to be treated by his wife that way when it's his turn at the relationship game? If you don't think the kids are watching, think again, they're recording all of it, at this early age, their brains are made to record everything.
Seriously I think you cut her too much slack, when she starts her oscar winning performances just change the channel and tune out - you give her too much attention even with your minimal attention that you're currently giving her and it bothers her to no end.
