Amanda, I totally understand that feeling of wanting to make him explain himself, and to make him see how badly he's fucked up. I've been there. But I think what it's really about is wanting to make him REGRET what he's done and come grovelling back to you. Unfortunately with people like this, they only regret their actions (if they ever do) after several cycles of this behaviour, when eventually something cataclysmic makes them face up to what they are really like. Don't waste your time hoping that you will be THE ONE who makes him have this epiphany. If it turns out that way, then so be it, but by then with a bit of luck you'll be on your way and no longer interested. Then he will really learn something useful from the experience.
While you continue to call him wanting answers, discussing the ins and outs with the other woman (bear in mind that of course, to her, YOU'RE the other woman), you are feeding his egocentric behaviour even further. Two women fighting for me! Wow, I must be a REALLY big man! I bet I can keep them both dangling till I decide which one I like the best. Oh purleese. You and your DD deserve a whole lot better than anything this knob can offer.
YOu will feel like crap for a few weeks, but it WILL get better, it DOES get easier, and you will be stronger and wiser when a new man comes along. Do you think this episode augurs well for the future with this one, when you're not even living together yet and he still won't behave like a grown-up and treat you with some respect?
Please, think about what you would be saying to a friend of yours in this situation. I would say, "Walk away with your dignity intact, honey, and be glad you found out what he's like sooner rather than later". Right now he is all you can think of and it's hard to imagine life with anyone else, but every day it will get a little easier and by Christmas (parties! new people!) I reckon you might be scanning the horizon and seeing a whole new raft of prospctive Mr Rights.