OP I understand all of what you're saying. I've been there, bought the t-shirt. Had to endure horrendous mess from my ex.
However, as a previous poster said - this is all fairly standard in divorces. It's so common it's untrue! To you at the time it feels like you're the only one.
We had all of this. Spent hours putting together a dossier of unreasonable behaviour - at pick-up, around sleeping conditions for the children. Etc. You know what? The courts weren't even remotely interested.
Unless the children are unsafe, they won't want to know. Their starting point (and end point) is the children. They're not interested in the rights or wrongs of the separation - whether affair, unreasonable behaviour, whatever. It's all completely irrelevant to them.
Also completely irrelevant is that fact that he wasn't particularly hands on before. Also completely normal. They would say he was out at work providing.
Their starting point is that the children need both parents.
I wouldn't present in this manner at a court IOP - unfortunately if you do, you will look like the unreasonable one. Take it from one who knows!
Honestly - please don't waste your time and emotion being angry and analysing his motives. You can't control what he does - only your reactions. So let him do it, keep the diary (nothing wrong in that - it's often advised by solicitors, I do it sometimes) and whatever else.
If it's any consolation, 5 years down the line, my ex still thinks he's 50/50. He's not! Constantly asking me to have them. I will do happily!
Good luck. But please heed the advice given for your own sake.