Chipmunk welcome to SI. as someone said to me when i first arrived...this is the club nobody wants to join, but everyone is glad they found!
Please consider counselling for yourself, many marriage counsellors preference is to have each person in IC before or as they start MC. It is difficult to see a joint MC when you have feelings of your own that you have not confronted.
Most importantly take care of you and your children. Get lots of fluids and try to eat light but nutritious meals. Get plenty of rest. Once your mind is a bit more settled consider reading and implementing the 180 for yourself, to get some distance and perspective.
You don't say if your WH is NC or if the A has ended. If it has not you May want to consider getting a consult with a lawyer. You don't have to file for divorce just get info about what your rights are in case the worst happens.
Know that there is no time line to anyone's healing, we are all different and progress at different rates. You are grieving and will go the stages of grief. Come here and read lots, it has been the best thing for me. You will get lots of advice, take what you feel works for you and leave the rest.
Good luck, I hope you find some peace on this journey.(((hugs)))