hi there,
I can't advise on the finances so I won't - someone who knows more should do that.

Do not encourage vists with the children IF possible. USE this time that he has re: his girlfriend as distraction for him. Some states recognize a legal separation if the spouse does not return to the family home for a year. This would give you a little 'legal leeway' when you need it (dont know what state laws you have??).

Try to reduce unnecessary communication with him. He's 'feeding' on it. He is SICK & no good can come of it. You cannot REASON with a sick person, who is manipulative and a pathological liar. You can't win. I read from a image posted on social network site (bit can't post site), it's like "giving the narc a bullet to shoot you because he missed the first time!"

See what legal recourse you can get. Try to take care of your mind too - this is 'WAR of the wills' & they have (!!) the edge, due to mental illness & lack of conscience

You are not alone. Best.