I am so sorry you're going through this double betrayal.
The ex gave the road map to his ow but I did all the dirty work for the ow. I basically did everything but bless their relationship with holy water. I did all the things that I wasnt supposed to do.
You sound strong. This is painful and it's natural to grieve and hurt. Sleep will be difficult but you have to make it happen somehow because when the adrenaline runs out, you'll crash.
Because your pain is so raw and recent, I say you should grieve as much as you want to as long as you and your kids are not endangered. Then after that, slowly try to start thinking of what to do.
You can call me Dory/ Grl.
As a wise fish once sang,"Just keep swimming!"
It's no use to go back to yesterday because I was a different person then.