And when you do get to speak with a lawyer, the objective of the meeting is to explore your legal options.
Find out what you CAN do legally to pressure her to act her age. Right now she likley doesn't think you have any leverage.
You may actually do better leaving yourself... and taking the kids with you... if by law you can do that and to offer her a visitation agreemetn or something.
I really don't know if you can ask HER to leave until she's done cheating, but you certainly are within your rights for you to leave... not sure about the kids... all of these things the lawyer should be able to offer more advice on.
Just make sure he knows you want to find out what leverage you have to apply pressure on her to act in the best interests of the marriage insted of destructively twoards the marriage as she is doing now.