Ah god, this is the worst part of dealing with an A father, the worst. The broken promises and broken hearts of children.
And he's bipolar. My experience wtih those guys is ugly. My unsolicited advice is to stop engaging with him, stop trying to make sense of naything he says, like how you keep moving the goal post.
Also I would work as quickly as possible to strip him of all parental rights. As many as possible. Later, or when you deem it appropriate, you can allow him to be around the kids. I've seen bipolar folks do insane things to and around their kids. INSANE!
I'm sorry you now have to deal with this as well.