The girlfriend is a convenience to you right now...She's going to keep him occupied while you get away. She's a gift to you; angels sent her.
Don't bother hating her: she didn't break any vows to you, he did, and if it wasn't her, it would be someone else. Obviously, she sees things from HIS viewpoint, so just ignore her--delete her messages unread. Change your number.
And him? Well, he's gone, Avani. He's got a new girlfriend. That's probably why he can hug you like it's all okay: he's moved on, and you mean nothing to him now. Sorry to say it so brutal, but it's brutal time for you.
The children love their father... well, yes, sure they do. And they love their mother and they can see what is going on. Who can explain your son's comment about their dad and girlfriend not arguing all weekend? What does that mean? The kids want to live happy, peaceful lives; I'm sure they'd prefer it was you and their dad, but that is not possible, clearly. I'm sure they are very wierded out by what's going on, but they just spent a relatively peaceful weekend with their dad and a woman who is drunk with delusion herself about what kind of a guy she's got on her hands.
Life has thrown you a curve ball; you have to decide now if you're going to take a swing or hope for a better pitch. You might not get one. I think you need to SWING right now before Girlfriend wises up and sends him back to your house. And boy, will he be mad at you then. And if the kids end up getting hurt, Avani... the State could well blame you for exposing them to known danger, imprison you, and take them from you. You, Earthmama, are what stands between your children and potential harm from an abusive man. You gave birth to five children... you can move MOUNTAINS to get your babies to fresh air. Make them proud, show them how to stay safe, show them that you WILL be there for them for the rest of their lives.
It is no longer your business how they will interact with their father in the future... your business is ensuring their safety today and for the next few years while you take a wait and see attitude about Daddy and his mental health. The kids might "be mad" at you, blame you, etc., but, that's just normal lashing out and not to be taken personally. They will understand later on, what you did for them. Or not. Does it matter? Isn't it just enough that you will have kept your children safe and kept their beloved mother safe, and maybe their dad coincidentally out of jail for harming you, by not being anywhere he could get to you?