You had a double betrayal and you have a new baby to boot. You are NOT going to just get over it. And anyone that tells you that you have my permission to smack them upside the head. No, really.
You never ever expected this. Nothing can prepare you for this.
This is not "irreconcilable differences". This is bigger and way worse than you ever thought possible. This is ultimate betrayal. This has hurt you deep to the core. This has shaken everything that you thought you were, made you question everything that you have ever done.
No one can or will really understand unless they have been through it. And even then, every situation is different.
You do not need to "move on" or "get over it". You need to heal. Healing takes time. Healing takes work. Healing takes patience. You have just been run over by an emotional Mac Truck. You are broken mentally and emotionally.
Your family and friends do not see the injuries, but they are there. And it takes the same amount of time and work to heal from this as it does from a bad auto accident and you just had a baby too. You are tired, worn out and exhausted. (((BIG HUGS)))
IMO, you do need to talk about it. Write about it. You will not "get over" this a couple months or even a year. You WILL begin to heal, but you it takes a long time to heal completely. Cry and scream and beat up the garbage can.
Get your anger and disappointment and hurt out.
Do not stuff it down just because someone else expects you to.
This healing time is YOUR time. It is your time to take control of your life and your own emotions and healing. You own it and you get to decide how it will work and how long it will take to heal.
Has your husband shown any remorse? Are you sure there is NC? Is IC possible for you?
I am so sorry you are still hurting. Hug that baby and know that we are all here for you.