Saw your new post (just before sending mine, lol).

Good for you!!!!!!!
Hint: don't bother trying to figure out why he is that way. It doesn't change anything. Enough time's been spent on him anyway. It is YOUR time!
And it's not just like escaping a captive situation, it is escaping a captive situation! If not physically, mentally.

Stay strong and never look back! So proud of you.

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(I've erased most of my original response, but if it is ok, would like to keep just a bit of it, if it may be of help at any future point for you or anyone in this situation.) Here are the major points:

There's nothing bipolar about that at ALL.

I've been on these forums for 6 years and have read thousands of posts. Honestly? I can't recall reading of such consistently infantile behavior.

He is an abuser, no ifs ands or buts about it. Surely this is not behavior you want modelled for your children. If for any reason you find it difficult to get rid of him for your own good, do it for their sakes.

Read CopperStar's post again. And again. It is spot on. If you ever feel waffle-y, read it again. As many times as is needed.