I have no idea what the reality is, but I am seeing so many red flags in (what is left of) your posts. A seriously lame excuse for not having the kids more often, yours (and presumably his) characterization of the soon-to-be-ex-wife as 100% wrong and manipulative, moving on to a new relationship before the dust has even settled on the old one, wanting to introduce girlfriend to kids, and generally how "effing nuts" the situation is while at the same time you two are making major life decisions.
I can't help but guess that you're moving way too fast, despite how well you know him. You're in "honeymoon phase", but a special kind of honeymoon phase where it's "us against the world" or, in your case, "us against the big-bad-ex-wife". You are, in all likelihood, not seeing this for what it is. He surely isn't--as someone who has been through a divorce, it takes a long, long time to get true perspective, decompress and figure out what really happened in the marriage. On the internet, every ex is crazy, abusive, insane and ridiculous, but in real life, the ones that are truly scum are few and far between. Someone claiming that their ex is horrible is a huge red flag that they don't have perspective on themselves and their part in the relationship.
Case in point: when my divorce first happened, everything was 100% my ex's fault and he was evil and lazy and horrible and a terrible father. Now, many years later, I can honestly point to lots of things I should have done in my marriage and lots of things that were 100% my fault. My ex is still an alcoholic and does not support his children financially in any way and never will, but I no longer see myself as the innocent victim in this. Interestingly enough, my ex, who has leapfrogged from relationship to relationship without respite, still believes I am 100% at fault and has never grown to see his issues. He tells everyone he meets that he drinks excessively because he is STILL recovering from living with me. Ha ha!
What I'm trying to say here is that despite knowing him from work, despite having gone through this "war" "together", you have no idea who you're living with yet. He has no idea who he is yet. Take it slowly for your own sake, and for those poor kids.