His behavior is mentally abusive, what kind of father/husband would rather party than caring to his own children when he know that his wife is in need of help.
Make sure to document his actions and his words, you will need those proofs in case of a divorce or a separation to show his lies.
Don't answer any more message/email from that woman, obviously she is deeply emotionally involved with him and is not a friend but rather an enemy of your marriage.
Accept the help of your family and friends, you need it, we are not super humans and it seems that you are getting burned out. You are now the only sane parent left for your children.
The more you will try to pursue him, the further he will go away and the angrier he will be.
I totally understand how badly you want him to be present and responsible for his own children but sadly he is infatuated with someone and limerence took over. Nothing you can say or do will make him change his behavior. The only resource you have right now is to detach from him, I know it's heart wrenching specially with a newborn. When you detach you are protecting yourself, stopping/decreasing fights and de facto removing any more causes he can make up to justify his behavior by blaming you. Right now, he is very aggressive toward you because he needs to find excuses to justify his actions, he knows deep down that people will judge him down the road so he needs to create a story to validate his decisions.
You did nothing to deserve to be treated that way, you are not the cause of his behavior. Step back, let him deal with his issues. The thread on detachment is excellent, please for your own sanity read it. I know how you feel I went though that nightmare, it was hell at home when the OW1 started to push him to ask for a divorce.
Me 52+ WH 57+ Married 20 + Piecing since 2016 (ready to give up...)
