This is still very very new for you. Day 12, although it feels like and eternity, it is not. Your mind is still processing 100 emotions at once ( completely normal ).
You are not pathetic. You are devastated. BIG difference.
First, as I am sure you have read here. This is NOT your fault. You cannot control the actions of your husband.
He made the conscience choice to cheat. He did this without your consistent.
You are in fear or flight mode. You need to know and yet you don't want to know ( again, normal )
I would recommend IC counseling on your own so you can get your bearings and understand what you want your reality to be going forward. IC will be about you finding your place, dealing with your thoughts/feelings.
Please convey he needs NC, to be honest, and getting tested.
IF he truly wants to R then he will do WHATEVER you need him to do.
MC will be about the relationship.
It is a long, tough road but you can make it to the other side one way or another.
Look on the library for the timeline for healing. Not to depress you but to help you understand healing is a process.
TIME is the only way.
Sending healthy healing hugs.