Ok you've had some really sensible advice but you didn't come here for that, you came here to try and rationalise your behaviour.
I'll say it, you're being so unreasonable that I feel even AIBU isn't harsh or real enough for you.
You sound unhinged.
You sound possessive and obsessive and if your EX was my current partner, I would not even be wasting my time with you or accommodating your pathetic behaviour.
Your EX will eventually, if he hasn't already, realise what a drain on his life you are and hopefully he will formalise contact arrangements that you will NOT be part of.
YOU are confusing your poor children by not teaching them healthy life lessons.
All it will take is a strong, loving, confident and independent woman to show him what a normal person does when a relationship breaks down, children or no children and he will absolutely and rightly so change your setup. I hope his current partner is that person.
Oh and you do know, birthing his children does not give you exclusive rights for life over him, you're not in a special category and ultimately he still left you, ask yourself why?
He can and more than likely will have children with someone else and you'll be there all bitter and twisted about it.
Stop this drama.
Have some self respect and let him go, he has clearly let you go, and this is from someone who is an ex-wife with 3 children with her ex-husband and I would never behave the way you do because I'm not crazy.